ABCB1 and ERCC1 gene polymorphisms are associated with nephro- and hepatotoxicity to carboplatin/paclitaxel-based chemotherapy in patients with gynecologic cancers.

BACKGROUND: Paclitaxel/carboplatin combination is the standard chemotherapeutic protocol for gynecologic cancers, but severe toxicities may compromise treatment. There is great inter-individual variability regarding the incidence and severity of toxicities, which may be due to single-nucleotide polymorphisms (SNPs) affecting drug disposition or cellular sensitivity. Here we investigate the impact of selected SNPs in ERCC1, ABCB1, CYP2C8, and CYP3A5 genes on the incidence of severe toxicities, including nephro- and hepatotoxicity. METHODS: A cohort of 507 gynecological cancer patients receiving paclitaxel/carboplatin was recruited at the Brazilian National Cancer Institute (INCA-Brazil). Clinical data were obtained during routine consultations or from electronic medical records. Toxicities were graded according to the Common Terminology Criteria for Adverse Events (CTCAE 5.0). Genotyping was performed using real-time PCR. RESULTS: ABCB1 c.1236C>T was associated with moderate-to-severe (grades 2-4) nephrotoxicity (ORadjusted 2.40; 95% CI 1.39-4.15), even after adjustment for age (≥ 65) and diabetes. The risk association between ABCB1 c.1236C>T and moderate-to-severe nephrotoxicity following paclitaxel/carboplatin chemotherapy was also present among non-diabetic patients (ORadjusted 2.16; 95% CI 1.22-3.82). ERCC1 c.118C>T was the only individual variable associated with an increased risk for moderate-to-severe (grades 2-4) hepatotoxicity (OR 3.71; 95% CI 1.08-12.77), severe nausea (OR 4.18; 95% CI 1.59-10.95), and severe myalgia (OR 1.95; 95% CI 1.12-3.40). CONCLUSIONS: ABCB1 c.1236C>T and ERCC1 c.118C>T might serve as potential biomarkers for the risk of moderate-to-severe toxicities to carboplatin/paclitaxel chemotherapy of gynecological cancers.

Impact of gene polymorphisms on the systemic toxicity to paclitaxel/carboplatin chemotherapy for treatment of gynecologic cancers.

PURPOSE: Gynecologic malignancies are often detected in advanced stages, requiring chemotherapy with taxane/platinum combinations, which may cause severe toxicities, such as neutropenia and peripheral neuropathy. Gene polymorphisms are suspected as possible causes for the interindividual variability on chemotherapy toxicities. OBJECTIVE: To evaluate the role of ABCB1 1236C>T, 3435C>T; CYP2C8*3; CYP3A5*3C variants on paclitaxel/carboplatin toxicities. METHODS: A cohort of 503 gynecologic cancer patients treated with paclitaxel/carboplatin at the Brazilian National Cancer Institute (INCA-Brazil) was recruited (2013-2017). Polymorphisms were genotyped by real-time PCR, and toxicities were evaluated by patients' interviews at each chemotherapy cycle and by data collection from electronic records. The association of clinical features and genotypes with severe toxicities was estimated using Pearson's Chi square tests and multiple regression analyses, with calculation of adjusted odds ratios (ORadjusted), and respective 95% confidence intervals (95% CI). RESULTS: CYP2C8*3 was significantly associated with increased risks of severe (grades 3-4) neutropenia (ORadjusted 2.11; 95% CI 1.24-3.6; dominant model) and severe thrombocytopenia (ORadjusted 4.93; 95% CI 1.69-14.35; recessive model), whereas ABCB1 variant genotypes (ORadjusted 2.13; 95% CI 1.32-3.42), in association with CYP2C8*3 wild type (GG) (ORadjusted 1.93; 95% CI 1.17-3.19), were predictive of severe fatigue. CONCLUSIONS: The present study suggests that CYP2C8*3 is a potential predictor of hematological toxicities related to paclitaxel/carboplatin treatment. Since hematological toxicities, especially neutropenia, may lead to dose delay or treatment interruption, such prognostic evaluation may contribute to clinical management of selected patients with paclitaxel-based chemotherapy.

Epidermal growth factor receptor gene polymorphisms are associated with prognostic features of breast cancer.

BACKGROUND: The epidermal growth factor receptor (EGFR) is differently expressed in breast cancer, and its presence may favor cancer progression. We hypothesized that two EGFR functional polymorphisms, a (CA)n repeat in intron 1, and a single nucleotide polymorphism, R497K, may affect EGFR expression and breast cancer clinical profile. METHODS: The study population consisted of 508 Brazilian women with unilateral breast cancer, and no distant metastases. Patients were genotyped for the (CA)n and R497K polymorphisms, and the associations between (CA)n polymorphism and EGFR transcript levels (n = 129), or between either polymorphism and histopathological features (n = 505) were evaluated. The REMARK criteria of tumor marker evaluation were followed. RESULTS: (CA)n lengths ranged from 14 to 24 repeats, comprehending 11 alleles and 37 genotypes. The most frequent allele was (CA)16 (0.43; 95% CI = 0.40-0.46), which was set as the cut-off length to define the Short allele. Variant (CA)n genotypes had no significant effect in tumoral EGFR mRNA levels, but patients with two (CA)n Long alleles showed lower chances of being negative for progesterone receptor (ORadjusted = 0.42; 95% CI = 0.19-0.91). The evaluation of R497K polymorphism indicated a frequency of 0.21 (95% CI = 0.19 - 0.24) for the variant (Lys) allele. Patients with variant R497K genotypes presented lower proportion of worse lymph node status (pN2 or pN3) when compared to the reference genotype Arg/Arg (ORadjusted = 0.32; 95% CI = 0.17-0.59), which resulted in lower tumor staging (ORadjusted = 0.34; 95% CI = 0.19-0.63), and lower estimated recurrence risk (OR = 0.50; 95% CI = 0.30-0.81). The combined presence of both EGFR polymorphisms (Lys allele of R497K and Long/Long (CA)n) resulted in lower TNM status (ORadjusted = 0.22; 95% CI = 0.07-0.75) and lower ERR (OR = 0.25; 95% CI = 0.09-0.71). When tumors were stratified according to biological classification, the favorable effects of variant EGFR polymorphisms were preserved for luminal A tumors, but not for other subtypes. CONCLUSIONS: The data suggest that the presence of the variant forms of EGFR polymorphisms may lead to better prognosis in breast cancer, especially in patients with luminal A tumors.

Role of vascular endothelial growth factor polymorphisms (-2578C>A, -460 T>C, -1154G>A, +405G>C and +936C>T) in endometriosis: a case-control study with Brazilians.

BACKGROUND: Endometriosis is regarded as a complex and heterogeneous disease in which genetic and environmental factors contribute to the phenotype. The Vascular Endothelial Growth Factor (VEGF) plays important roles in the pathogenesis of endometriosis. The present study was aimed at investigating the contribution of VEGF polymorphisms as risk factors for the development of endometriosis. This is the first study to evaluate the combined influence of the five most common VEGF polymorphisms. METHODS: This study was conducted at two hospitals from the Brazilian public health system, and comprised 294 women submitted to laparoscopic or laparotomy surgery: 182 patients had a histologically confirmed diagnosis of endometriosis (cases), whereas 112 had no evidence of the disease (controls). The VEGF polymorphisms were determined by TaqMan real-time polymerase chain reaction. The odds ratio (OR) with their 95% confidence intervals (CI) were calculated using an unconditional logistic regression model. RESULTS: Endometriosis patients and controls did not differ regarding age distribution, whereas the body mass index was significantly lower in endometriosis patients, when compared with controls (23.1 ± 3.9 versus 27.3 ± 5.9, P < 0.001). The evaluation of gynecological symptoms, including dysmenorrhea, non-cyclic chronic pelvic pain, dyspareunia and infertility, indicates significantly higher prevalences among endometriosis cases. The variant allele -1154A was significantly associated with endometriosis, either considering all cases (OR: 1.90, 95% CI: 1.23-2.97), deep infiltrating endometriosis (DIE) (OR: 1.83, 95% CI: 1.16-2.90) or moderate and severe endometriosis (stages III-IV) (OR: 1.97, 95% CI: 1.21-3.19). No significant differences were found in allele or genotype distributions of the -2578C > A, -460 T > C, +405G > C and +936C > T polymorphisms between endometriosis cases and controls. A total of six haplotypes were inferred derived from four polymorphisms (-2578C > A, -460 T > C, -1154G > A and +405G > C). There was a protective association between CCGG haplotype and endometriosis, either considering all cases (OR: 0.36, 95% CI: 0.15-0.86), DIE (OR: 0.37 95% CI: 0.15 - 0.90) or stages III-IV (OR: 0.35 95% CI: 0.13 - 0.95). CONCLUSIONS: The present results indicate a positive association between VEGF -1154G > A and the risk of developing endometriosis, whereas the CCGG haplotype may be protective against the development of disease.

High mobility group box 1, ATP, lipid mediators, and tissue factor are elevated in COVID-19 patients: HMGB1 as a biomarker of worst prognosis.

The severe acute respiratory syndrome coronavirus 2, the agent of the ongoing coronavirus disease 2019 (COVID-19) pandemic, has spread worldwide since it was first identified in November 2019 in Wuhan, China. Since then, progress in pathogenesis linked severity of this systemic disease to the hyperactivation of network of cytokine-driven pro-inflammatory cascades. Here, we aimed to identify molecular biomarkers of disease severity by measuring the serum levels of inflammatory mediators in a Brazilian cohort of patients with COVID-19 and healthy controls (HCs). Critically ill patients in the intensive care unit were defined as such by dependence on oxygen supplementation (93% intubated and 7% face mask), and computed tomography profiles showing ground-glass opacity pneumonia associated to and high levels of D-dimer. Our panel of mediators included HMGB1, ATP, tissue factor, PGE2 , LTB4 , and cys-LTs. Follow-up studies showed increased serum levels of every inflammatory mediator in patients with COVID-19 as compared to HCs. Originally acting as a transcription factor, HMGB1 acquires pro-inflammatory functions following secretion by activated leukocytes or necrotic tissues. Serum levels of HMGB1 were positively correlated with cys-LTs, D-dimer, aspartate aminotransferase, and alanine aminotransferase. Notably, the levels of the classical alarmin HMGB1 were higher in deceased patients, allowing their discrimination from patients that had been discharged at the early pulmonary and hyperinflammatory phase of COVID-19. In particular, we verified that HMGB1 levels above 125.4 ng/ml is the cutoff that distinguishes patients that are at higher risk of death. In conclusion, we propose the use of serum levels of HMGB1 as a biomarker of severe prognosis of COVID-19.

Polymorphisms in cycloxygenase-2 gene and breast cancer prognosis: association between PTGS2 haplotypes and histopathological features.

Cyclooxygenase-2 (COX-2) overexpression is associated with worse prognosis in breast cancer. COX-2 is encoded by a polymorphic gene, called PTGS2, and its expression may be genetically influenced. In this article, we investigate the association between PTGS2 haplotypes and histopathological parameters with prognostic value on the clinical outcome of breast cancer. The study involved 606 women under current treatment for non-metastatic breast cancer. Patients were genotyped for rs689465, rs689466, rs20417, and rs5275, and their haplotypes were inferred. The distribution of PTGS2 genotypes and haplotypes was evaluated according to histopathological categorical groups used for prognostic determination of low/intermediate versus high risk of tumor recurrence. Our results indicate positive associations between variant genotypes of rs689465 and estrogen receptor negativity (OR: 1.59, 95% CI: 1.04-2.44, P: 0.02) or HER2 positivity (OR: 1.79, 95% CI: 1.00-3.18, P: 0.03), and between variant genotypes of rs20417 and estrogen receptor negativity (OR: 1.75, 95% CI: 1.15-2.57, P: 0.005), progesterone receptor negativity (OR: 1.56, 95% CI: 1.09-2.22, P: 0.01) or HER2 positivity (OR: 1.80, 95% CI: 1.04-3.13, P: 0.02). In contrast, variant genotypes of rs689466 are negatively associated with estrogen receptor negativity (OR: 0.57, 95% CI: 0.33-0.98, P: 0.03). A total of eight haplotypes were inferred, and there was a significant difference in their distribution as a function of tumor size (P: 0.011), estrogen receptor status (P: 0.018), and HER2 status (P: 0.025). PTGS2 haplotype *7 (formed by rs689465G, rs689466A, rs20417C, and rs5275T) is positively associated with higher tumor size (OR: 3.72, 95% CI: 1.19-11.22, P: 0.006), estrogen receptor negativity (OR: 2.43, 95% CI: 0.97-5.98, P: 0.032), progesterone receptor negativity (OR: 2.58, 95% CI: 1.05-6.39, P: 0.02), and HER2 positivity (OR: 4.17, 95% CI: 1.19-14.44, P: 0.007). Our results suggest that PTGS2 haplotype *7 may contribute to higher growth of untreated breast cancer and that PTGS2 haplotypes need to be considered in the characterization of breast cancer prognosis.

Polymorphisms in regulatory regions of cyclooxygenase-2 gene and breast cancer risk in Brazilians: a case-control study.

BACKGROUND: Cyclooxygenase-2 (COX-2) is up-regulated in several types of cancer, and it is hypothesized that COX-2 expression may be genetically influenced. Here, we evaluate the association between single-nucleotide polymorphisms (SNPs) in the COX-2 gene (PTGS2) and the occurrence of breast cancer among Brazilian women. METHODS: The study was conducted prospectively in two steps: First, we screened the promoter region and three fragments of the 3'-untranslated region of PTGS2 from 67 healthy Brazilians to identify SNPs and to select those with a minor allele frequency (MAF) of at least 0.10. The MAF of these selected SNPs was further characterized in 402 healthy volunteers to evaluate potential differences related to heterogeneous racial admixture and to estimate the existence of linkage disequilibrium among the SNPs. The second step was a case-control study with 318 patients and 273 controls designed to evaluate PTGS2 genotype- or haplotype-associated risk of breast cancer. RESULTS: The screening analysis indicated nine SNPs with the following MAFs: rs689465 (0.22), rs689466 (0.15), rs20415 (0.007), rs20417 (0.32), rs20419 (0.015), rs5270 (0.02), rs20424 (0.007), rs5275 (0.22) and rs4648298 (0.01). The SNPs rs689465, rs689466, rs20417 and rs5275 were further studied: Their genotypic distributions followed Hardy-Weinberg equilibrium and the MAFs were not affected by gender or skin color. Strong linkage disequilibrium was detected for rs689465, rs20417 and rs5275 in the three possible pairwise combinations. In the case-control study, there was a significant increase of rs5275TC heterozygotes in cases compared to controls (OR = 1.44, 95% CI = 1.01-2.06; P = 0.043), and the haplotype formed by rs689465G, rs689466A, rs20417G and rs5275C was only detected in cases. The apparent association with breast cancer was not confirmed for rs5275CC homozygotes or for the most frequent rs5275C-containing haplotypes. CONCLUSIONS: Our results indicate no strong association between the four most frequent PTGS2 SNPs and the risk of breast cancer.

The -1195A>G polymorphism in Ciclooxygenase-2 gene is associated with lower risk of endometriosis.

OBJECTIVES: This study aimed to evaluate the potential role of the PTGS2 single nucleotide polymorphisms (SNPs) -1195 A>G and +8473 T>C in endometriosis' development, and characterizing their association with the prognostic features of the disease. STUDY DESIGN: DNA from 254 women with endometriosis and 267 controls, recruited from two reference hospitals from the Brazilian public health system, were genotyped using TaqMan allelic discrimination assays. The association between SNPs and endometriosis features was evaluated by multivariate logistic regression, using the adjusted odds ratios (OR) with their respective 95% confidence intervals (95% CI). RESULTS AND CONCLUSION: There were significant differences between cases and controls regarding age (P < 0.001), body mass index (BMI) (P = 0.001), educational level (P < 0.001), physical activity (P = 0.003), smoking status (P < 0.001), contraception use (P = 0.02), family history of endometriosis (P = 0.002) and all symptoms (P < 0.001). The distribution of -1195 A > G was statistically different between the groups, suggesting a lower risk of developing the disease for the carriers of the -1195 GG genotype (OR = 0.19; 95% CI = 0.04 - 0.93). No differences were found for the +8473 T>C between the two groups and neither in prognostic features of the disease for both PTGS2 SNPs. In conclusion, PTGS2 -1195A>G SNP was negatively associated with development of endometriosis and the two groups were statistically different regarding age, BMI, educational level, physical activity, smoking status, contraception use, history of endometriosis and all endometriosis symptoms.

A novel and simple LC-MS/MS quantitative method for dextromethorphan and dextrorphan in oral fluid.

Aim: To develop and validate a simple method using LC-MS/MS for determination of dextromethorphan (DXM) and dextrorphan (DT) in human oral fluid. Results: Following protein precipitation, chromatographic separation used a phenyl column with isocratic elution (1 ml/min) of 10 mM ammonium-formate buffer and acetonitrile (65:35; v/v) with 0.1% formic acid. Retention times were 2.6 min for DT and 5 min for DXM. Total run time was 7 min. The intra- and inter-assay deviations (accuracy) for DT (1-100 ng/ml) and DXM (5-1000 ng/ml) ranged from -13.6 to 8.8% and -9.6 to 5.7%, respectively. Precision variations were ≤7.5%. Matrix effect was ≤11.8%. Conclusion: This method may prove helpful for quantification of DT and DXM in oral fluid for either clinical or toxicological purposes.

Study of membrane potential in T lymphocytes subpopulations using flow cytometry.

BACKGROUND: Ion channels are involved in the control of membrane potential (psi) in a variety of cells. The maintenance of psi in human T lymphocytes is essential for T-cell activation and was suggested to depend mostly on the voltage-gated Kv1.3 channel. Blockage of Kv1.3 inhibits cytokine production and lymphocyte proliferation in vitro and suppresses immune response in vivo. T lymphocytes are a heterogeneous cell population and the expression of Kv1.3 varies among cell subsets. Oxonol diBA-C4-(3) was used to determine psi by flow cytometry. The presence of distinct T cell subsets was evaluated by immunophenotyping techniques and the contribution of Kv1.3 channels for the maintenance of psi was investigated using selective blockers. RESULTS: The distribution of psi in T lymphocytes varied among blood donors and did not always follow a unimodal pattern. T lymphocytes were divided into CD3+/CD45RO- and CD3+/CD45RO+ subsets, whose peak channel values of psi were -58 +/- 3.6 mV and -37 +/- 4.1 mV, respectively. MgTX (specific inhibitor of Kv1.3 channels) had no significant effect in the psi of CD3+/CD45RO- subsets but depolarized CD3+/CD45RO+ cells to -27 +/- 5.1 mV. CONCLUSION: Combination of optical methods for determination of psi by flow cytometry with immuophenotyping techniques opens new possibilities for the study of ion channels in the biology of heterogeneous cell populations such as T lymphocyte subsets.

PTGS2 polymorphism rs689466 favors breast cancer recurrence in obese patients.

Breast cancer is the leading cancer among women, and its increasing incidence is a challenge worldwide. Estrogen exposure is the main risk factor, but obesity among postmenopausal women has been shown to favor disease onset and progression. The link between obesity and mammary carcinogenesis involves elevated estrogen production and proinflammatory stimuli within the adipose tissue, with activation of the cyclooxygenase-2 pathway. Here, we evaluate the impact of the four most common cyclooxygenase-2 gene polymorphisms (rs689465, rs689466, rs20417 and rs20417), in combination with obesity, on the risk of breast cancer progression in a cohort of Brazilian breast cancer patients (N = 1038). Disease-free survival was evaluated using Kaplan-Meier curves, with multivariate Cox proportional hazards regression models for calculation of adjusted hazard ratios (HRadj). Obesity did not affect disease progression, whereas rs689466 variant genotypes increased the recurrence risk among obese patients (HRadj = 2.5; 95% CI = 1.4-4.3), either for luminal (HRadj = 2.2; 95% CI = 1.1-4.2) or HER2-like and triple-negative tumors (HRadj = 3.2; 95% CI = 1.2-8.5). Likewise, the haplotype *4, which contains variant rs689466, was associated with shorter disease-free survival among obese patients (HRadj = 3.3; 95% CI = 1.8-6.0), either in luminal (HRadj = 3.5; 95% CI = 1.6-7.3) or HER2-like and triple-negative (HRadj = 3.1; 95% CI = 1.1-8.9) tumors. Such deleterious impact of variant rs689466 on disease-free survival of obese breast cancer patients was restricted to postmenopausal women. In conclusion, cyclooxygenase-2 genotyping may add to the prognostic evaluation of obese breast cancer patients.

Combined effect of vascular endothelial growth factor and its receptor polymorphisms in endometriosis: a case-control study.

OBJECTIVE: Endometriosis is a multifactorial gynecological disease, whose pathogenesis is crucially dependent on angiogenesis, which is signaled via vascular endothelial growth factor (VEGF) and its receptor (VEGFR2). We hypothesize that single nucleotide polymorphisms (SNPs) in VEGF and VEGFR2 genes may influence the onset and/or the progression of endometriosis. The main aim of this study was to investigate the contribution of VEGF and VEGFR2 SNPs as risk factors for endometriosis, as well as their association with endometriosis symptoms. STUDY DESIGN: A case-control study was conducted, involving 293 endometriosis patients and 223 controls, who were submitted to laparoscopic or laparotomy surgery at hospitals from the Brazilian public health system. Genotyping of VEGF (-2578C>A, -460T>C, -1154G>A, +405G>C and +936C>T) and VEGFR2 (-604T>C, 1192C>T) SNPs was performed by TaqMan real-time polymerase chain reaction. The association between SNPs and endometriosis, deep infiltrating endometriosis (DIE) or endometriosis symptoms was estimated by odds ratios (OR) with their 95% confidence intervals (CI), which were calculated using multivariate logistic regression models. RESULTS: VEGF variant alleles -2578A and -1154A were associated with increased endometriosis risk (OR: 1.39, 95% CI: 1.04-1.87 and OR: 1.63, 95% CI: 1.12-2.37, respectively), whereas VEGF 405C and VEGFR2 1192T were associated with lower risk of endometriosis (OR: 0.66, 95% CI: 0.43-1.00 and OR: 0.58, 95% CI: 0.40-0.84, respectively). The combination of wild-type genotypes of both VEGF -2578C>A and -1154G>A with variant genotypes of both VEGF +405G>C and VEGFR2 1192C>T showed the best protective effect against the development of endometriosis, either considering all cases (OR: 0.33, 95% CI: 0.12-0.89) or only DIE (OR: 0.30, 95% CI: 0.10-0.87). The combination of variant genotypes of VEGF -2578C>A, -1154G>A, +405G>C and VEGFR2 1192C>T was also protective against DIE (OR: 0.67, 95% CI: 0.46-0.96). VEGFR2 1192C>T were associated with reduced cyclical urinary complaints (OR: 0.40, 95% CI: 0.18-0.88). CONCLUSIONS: Our results indicate that VEGF SNPs -2578C>A and -1154G>A increase endometriosis risk, whereas VEGF +405G>C and VEGFR2 1192C>T are protective against disease development, with VEGFR2 1192C>T also reducing cyclical urinary symptoms. The combined analysis of VEGF-VEGFR2 genotypes suggests a gene-gene interaction in endometriosis susceptibility.

DNA repair genes PAXIP1 and TP53BP1 expression is associated with breast cancer prognosis.

Despite remarkable advances in diagnosis, prognosis and treatment, advanced or recurrent breast tumors have limited therapeutic approaches. Many treatment strategies try to explore the limitations of DNA damage response (DDR) in tumor cells to selectively eliminate them. BRCT (BRCA1 C-terminal) domains are present in a superfamily of proteins involved in cell cycle checkpoints and the DDR. Tandem BRCT domains (tBRCT) represent a distinct class of these domains. We investigated the expression profile of 7 tBRCT genes (BARD1, BRCA1, LIG4, ECT2, MDC1, PAXIP1/PTIP and TP53BP1) in breast cancer specimens and observed a high correlation between PAXIP1 and TP53BP1 gene expression in tumor samples. Tumors with worse prognosis (tumor grade 3 and triple negative) showed reduced expression of tBRCT genes, notably, PAXIP1 and TP53BP1. Survival analyses data indicated that tumor status of both genes may impact prognosis. PAXIP1 and 53BP1 protein levels followed gene expression results, i.e., are intrinsically correlated, and also reduced in more advanced tumors. Evaluation of both genes in triple negative breast tumor samples which were characterized for their BRCA1 status showed that PAXIP1 is overexpressed in BRCA1 mutant tumors. Taken together our findings indicate that PAXIP1 status correlates with breast cancer staging, in a manner similar to what has been characterized for TP53BP1.

Evaluation of the EGFR polymorphism R497K in two cohorts of neoadjuvantly treated breast cancer patients.

Pathological response of breast cancer to neoadjuvant chemotherapy (NAC) presents great variability, and new prognostic biomarkers are needed. Our aim was to evaluate the association of the epidermal growth factor receptor gene (EGFR) polymorphism R497K (rs2227983) with prognostic features and clinical outcomes of breast cancer, including the pathological response to NAC and the recurrence-free survival (RFS). Tumoral complete response (tCR) was defined by no remaining invasive cancer in the excised breast, whereas pathological complete response (pCR) was defined by no remaining invasive cancer both in the excised breast and lymph nodes. Two independent cohorts were analyzed: one from Brazil (INCA, n = 288) and one from The Netherlands (NKI-AVL, n = 255). In the INCA cohort, the variant (Lys-containing) genotypes were significantly associated with lower proportion of tCR (ORadj = 0.92; 95%CI = 0.85-0.99), whereas in the NKI-AVL cohort they were associated with tumor grade 3 (p = 0.035) and with triple-negative subtype (p = 0.032), but not with clinical outcomes. Such distinct prognostic associations may have arisen due to different neoadjuvant protocols (p < 0.001), or to lower age at diagnosis (p < 0.001) and higher proportion of tumor grade 3 (p = 0.018) at the NKI-AVL cohort. Moreover, NKI-AVL patients achieved better proportion of pCR (21.2% vs 8.3%, p < 0.001) and better RFS (HRadj = 0.48; 95% adjCI = 0.26-0.86) than patients from INCA. In conclusion, large scale studies comprehending different populations are needed to evaluate the impact of genome variants on breast cancer outcomes.

Loss of constitutive ABCB1 expression in breast cancer associated with worse prognosis.

ABCB1 gene encodes an adenosine 5'-triphosphate-binding cassette transporter, which not only confers multidrug resistance phenotype in malignant cells, but is also present in several nonmalignant tissues. For the last thirty years, ABCB1 expression in breast cancer has been described by many authors, but the extent of expression differs among the studies, and there is no consensus regarding its potential role in carcinogenesis or in the tumor response to antineoplastic drugs. This study aimed to characterize the expression of ABCB1 in breast tumors as a function of genetic, clinical, and histopathological variables. The ABCB1 expression was also evaluated in nonmalignant mammary tissues adjacent to tumors and in benign lesions. The detection of ABCB1 protein was performed by immunohistochemistry in tissue specimens of excised breasts obtained from a prospective cohort of Brazilian women with breast cancer. The association of ABCB1 protein levels with ABCB1 mRNA, gene polymorphisms, and clinical and histopathological variables was also evaluated. The Kaplan-Meier curves and multivariate Cox regression analyses were conducted to identify independent predictors of disease-free survival of patients with breast cancer. ABCB1 was detected in 86.3% (656) of breast tumors, 98.8% (606) of nonmalignant mammary tissue adjacent to tumors, and 100% (28) of benign lesions. Reduced ABCB1 protein levels in breast tumors was associated with triple-negative subtype (adjusted odds ratio [ORadj] =0.24; 95% confidence interval [CI] =0.13-0.45), lymph node status < pN2 (ORadj =0.27; 95% CI =0.10-0.71), tumor size >2 cm (ORadj =0.55; 95% CI =0.32-0.93), and hypertensive status (ORadj =0.42; 95% CI =0.24-0.73), and it was significantly associated with shorter disease-free survival, either for all breast cancer patients (p log-rank =0.012; hazard ratio [HR] =3.46; 95% CI =1.21-9.91) or for those with triple-negative tumors (p log-rank =0.007; HR =11.41; 95% CI =1.29-100.67). The loss of constitutive ABCB1 expression in breast cancer, especially in triple-negative tumors, seems to indicate a subgroup of worse prognosis.

Prognostic evaluation of VEGFA genotypes and haplotypes in a cohort of Brazilian women with non metastatic breast cancer.

Vascular Endothelial Growth Factor (VEGF) mediates angiogenesis, which is crucial for tumor development and progression. The present study aimed to evaluate the impact of VEGFA gene polymorphisms rs699947, rs833061, rs1570360, rs2010963 and rs3025039 on breast cancer features and prognosis. A cohort of Brazilian women (N = 1038) with unilateral non-metastatic breast cancer was evaluated. The association between VEGFA polymorphisms and histopathological features or pathological complete response (pCR) to neoadjuvant chemotherapy was evaluated by the Chi-square test, with calculation of the respective odds ratio (OR) and 95% confidence intervals (95% CI). The impact of individual categories on disease-free survival was evaluated using Kaplan-Meier curves and multivariate Cox proportional hazards regression models for calculation of adjusted hazard ratios (HRadjusted). Variant genotypes of rs699947 (CA + AA) were significantly associated with high-grade (G2 + G3) tumors (OR = 1.82; 95% CI = 1.15 - 2.89), and with shorter disease-free survival among patients treated with neoadjuvant chemotherapy followed by mastectomy (HRadjusted = 1.82; 95% CI = 1.16 - 2.86). Variant genotypes of rs833061 (TC + CC) were significantly associated with high-grade (G2 + G3) tumors (OR = 1.79; 95% CI = 1.12 - 2.84) and with positive lymph node status (OR = 1.34; 95% CI = 1.01 - 1.77), but showed no independent effect on disease-free survival. Variant haplotypes (*2 to *5) appear to favor pCR (OR = 7.1; 95% CI = 1.7 - 30.1). VEGFA genotyping may add to prognostic evaluation of breast cancer, with rs699947 being the most likely to contribute.

Influence of CYP2C9 genotypes on the pharmacokinetics and pharmacodynamics of piroxicam.

OBJECTIVE: Our objective was to evaluate the influence of cytochrome P450 (CYP) 2C9 polymorphisms on the pharmacokinetics and pharmacodynamics of the nonsteroidal anti-inflammatory drug piroxicam. METHODS: Thirty-five healthy subjects with CYP2C9 genotypes *1/*1 (n=17), *1/*2 (n=9), and *1/*3 (n=9) received a single oral dose of piroxicam (20 mg). Blood samples were collected at various time points up to 240 hours for measurements of the concentrations of piroxicam and thromboxane B2 (TXB2). RESULTS: Piroxicam's area under the plasma concentration-time curve from time 0 to infinity and oral clearance corrected for body weight were 154+/-37 microg.mL-1.h and 2.0+/-0.5 mL.h-1.kg-1, respectively, in CYP2C9*1/*1 individuals, as compared with 256+/-97 mL.h-1 (P=.002) and 1.3+/- 0.4 mL.h-1.kg-1 (P=.002), respectively, in CYP2C9*1/*2 individuals and 259+/- 95 mL.h-1 (P=.002) and 1.3+/- 0.4 mL.h-1.kg-1 (P=.002), respectively, in CYP2C9*1/*3 individuals. There were no significant differences between CYP2C9*1/*2 and CYP2C 9*1/*3 individuals in these pharmacokinetic parameters (P=.95 for area under the plasma concentration-time curve from time 0 to infinity and P=.94 for oral clearance corrected for body weight). The formation of TXB2, reflecting cyclooxygenase type 1 activity, showed significant differences in the area above the effect-time curves (expressed as percent of baseline TXB2.h) between CYP2C9*1/*1 (10,190 +/- 2632) and either CYP2C9*1/*2 (19,255+/-1,291 [P=.00003]) or CYP2C9*1/*3 (18,241+/- 2397 [P=.00003]). The minimum serum TXB2 concentration, however, did not differ among the different genotypes (P=.32, ANOVA). CONCLUSION: Piroxicam's oral clearance was impaired and its inhibitory effect on cyclooxygenase 1 activity was increased in CYP2C9*1/*2 or CYP2C9*1/*3 individuals, as compared with CYP2C 9*1 homozygous individuals.

CYP2C9 genotypes and the pharmacokinetics of tenoxicam in Brazilians.

OBJECTIVE: Cytochrome P450 (CYP) 2C9, the product of the polymorphic gene CYP2C9, provides the major catabolic pathway for several anti-inflammatory drugs, including tenoxicam. Our objectives were (1) to determine the frequency of 2 common CYP2C9 variant alleles (*2 and *3) in the Brazilian population and (2) to evaluate the effects of these polymorphisms on the pharmacokinetics of tenoxicam. METHODS: Polymerase chain reaction-restriction fragment length polymorphism methods were used to identify CYP2C9*2 and CYP2C9*3 in 331 healthy Brazilians, classified as white (n = 136), black (n = 77), or intermediate (n = 118). A validated HPLC procedure was used for measuring the plasma concentrations of tenoxicam, after single oral doses of 20 mg, administered to 21 individuals with CYP2C9*1/*1 (n = 12), CYP2C9*1/*2 (n = 4), or CYP2C9*1/*3 genotypes (n = 5), confirmed by deoxyribonucleic acid sequencing. A 2-compartment pharmacokinetic model was used for fitting the plasma concentration versus time data, and the individual model descriptive parameters were used to simulate the plasma tenoxicam concentrations during repeated dosing for 7 consecutive days. RESULTS: The frequencies of CYP2C9*1, CYP2C9*2, and CYP2C9*3 in the study population were 0.849, 0.086, and 0.065, respectively. The distribution of CYP2C9 alleles differed across the Brazilian color groups (P = .016), with the frequencies of the variant alleles being 2.5 to 3 times lower in black Brazilians than in white Brazilians (P = .003). After a single dose of tenoxicam, the area under the plasma concentration-time curve (AUC) from time 0 to infinity and the oral clearance of tenoxicam were 190 +/- 48 microg x mL(-1) x h and 113 +/- 30 mL x h(-1), respectively, in wild-type homozygous subjects (CYP2C9*1/*1), as compared with 261 +/- 14 microg x mL(-1) x h (P = .013) and 77 +/- 4 mL x h(-1) (P = .036), respectively, in CYP2C9*1/*2 heterozygous subjects and 335 +/- 126 microg x mL(-1) x h (P = .003) and 67 +/- 23 mL x h(-1) (P = .008) in CYP2C9*1/*3, respectively, heterozygous subjects. After 7 simulated daily doses, significant differences were observed between CYP2C9*1/*1 and CYP2C9*1/*3 individuals in relation to the minimum plasma (trough) tenoxicam concentration (Cmin, 5.2 +/- 1.3 microg x mL(-1) versus 7.6 +/- 2.6 microg x mL(-1); P = .021), maximum tenoxicam plasma concentration (Cmax, 7.4 +/- 1.9 microg x mL(-1) versus 10.5 +/- 3.0 microg x mL(-1); P = .020), and 24-hour AUC (152 +/- 39 microg x mL(-1) x h versus 219 +/- 72 microg x mL(-1) x h). No significant differences were observed in Cmin, Cmax, or AUC between CYP2C9*1/*2 and either CYP2C9*1/*1 or CYP2C9*1/*3 individuals. CONCLUSION: The allelic and genotypic frequencies of CYP2C9*1, *2, and *3 in white and black Brazilians are similar to those reported for other white (Caucasian) and black (African and African American) populations, respectively. Heterozygosis for CYP2C9*3, and to a lesser degree CYP2C9*2, increases the exposure to tenoxicam during single and repeated doses.

Shaker-type Kv1 channel blockers increase the peristaltic activity of guinea-pig ileum by stimulating acetylcholine and tachykinins release by the enteric nervous system.

1 A constant intraluminal pressure system was used to evaluate the effects of Kv1 channel blockers on the peristaltic activity of guinea-pig ileum. 2 The nortriterpene correolide, a non-selective inhibitor of all Kv1 sub-types, causes progressive and sustained reduction of the pressure threshold for eliciting peristaltic contractions. 3 Margatoxin (MgTX), alpha-dendrotoxin (alpha-DTX) and dendrotoxin-K (DTX-K), highly selective peptidyl inhibitors of certain Kv1 sub-types, cause immediate reduction of the pressure threshold. This effect subsides with time, irrespective of the peptides' concentration in the bath. In preparations pretreated with saturating concentrations of MgTX, correolide further stimulates the peristaltic activity. 4 Iberiotoxin (IbTX), a selective inhibitor of the high-conductance Ca(2+)-activated K(+) (BK) channels, and charybdotoxin (ChTX), which inhibits Kv1.2 and Kv1.3 as well as BK channels, fail to stimulate the peristaltic activity. 5 Blockade of muscarinic receptors by atropine reduces, and occasionally suppresses the peristaltic activity of guinea-pig ileum. In atropine-treated preparations, correolide and MgTX retain their abilities to reduce the pressure threshold and are able to restore the peristaltic reflex in the preparations where this reflex was suppressed by atropine. 6 The stimulatory effect of correolide and MgTX in atropine-treated preparations is abolished by subsequent addition of selective antagonists of both NK1 and NK2 receptors. 7 In conclusion, blockade of Kv1, particularly Kv1.1 channels, increases the peristaltic activity of guinea-pig ileum by enhancing the release of neurotransmitters at the enteric nervous system. In contrast, stimulation of the myogenic motility by blockade of BK channels does not affect the threshold for the peristaltic reflex.

Potassium channels in T lymphocytes: therapeutic targets for autoimmune disorders?

Human peripheral blood T lymphocytes possess two types of K(+) channels: the voltage-gated Kv1.3 and the calcium-activated IKCa1 channels. The use of peptidyl inhibitors of Kv1.3 and IKCa1 indicated that these channels are involved in the maintenance of membrane potential and that they play a crucial role in Ca(2+) signaling during T-cell activation. Thus, in vitro blockade of Kv1.3 and IKCa1 leads to inhibition of cytokine production and lymphocyte proliferation. These observations prompted several groups of investigators in academia and pharmaceutical companies to characterize the expression of Kv1.3 and IKCa1 in different subsets of human T lymphocytes and to evaluate their potential as novel targets for immunosuppression. Recent in vivo studies showed that chronically activated T lymphocytes involved in the pathogenesis of multiple sclerosis present unusually high expression of Kv1.3 channels and that the treatment with selective Kv1.3 inhibitors can either prevent or ameliorate the symptoms of the disease. In this model of multiple sclerosis, blockade of IKCa1 channels had no effect alone, but improved the response to Kv1.3 inhibitors. In addition, the expression of Kv1.3 and IKCa1 channels in human cells is very restricted, which makes them attractive targets for a more cell-specific and less harmful action than what is typically obtained with classical immunosuppressants. Studies using high-throughput toxin displacement, (86)Rb-efflux screening or membrane potential assays led to the identification of non-peptidyl small molecules with high affinity for Kv1.3 or IKCa1 channels. Analysis of structure-function relationships in Kv1.3 and IKCa1 channels helped define the binding sites for channel blockers, allowing the design of a new generation of small molecules with selectivity for either Kv1.3 or IKCa1, which could help the development of new drugs for safer treatment of auto-immune diseases.