Investigating the effects of PTEN mutations on cGAS-STING pathway in glioblastoma tumours.

BACKGROUND: PTEN is a tumour suppressor gene and well-known for being frequently mutated in several cancer types. Loss of immunogenicity can also be attributed to PTEN loss, because of its role in establishing the tumour microenvironment. Therefore, this study aimed to represent the link between PTEN and cGAS-STING activity, a key mediator of inflammation, in tumour samples of glioblastoma patients. METHODS: Tumour samples of 36 glioblastoma patients were collected. After DNA isolation, all coding regions of PTEN were sequenced and analysed. PTEN expression status was also evaluated by qRT-PCR, western blot, and immunohistochemical methods. Interferon-stimulated gene expressions, cGAMP activity, CD8 infiltration, and Granzyme B expression levels were determined especially for the evaluation of cGAS-STING activity and immunogenicity. RESULTS: Mutant PTEN patients had significantly lower PTEN expression, both at mRNA and protein levels. Decreased STING, IRF3, NF-KB1, and RELA mRNA expressions were also found in patients with mutant PTEN. Immunohistochemistry staining of PTEN displayed expressional loss in 38.1% of the patients. Besides, patients with PTEN loss had considerably lower amounts of IFNB and IFIT2 mRNA expressions. Furthermore, CD8 infiltration, cGAMP, and Granzyme B levels were reduced in the PTEN loss group. CONCLUSION: This study reveals the immunosuppressive effects of PTEN loss in glioblastoma tumours via the cGAS-STING pathway. Therefore, determining the PTEN status in tumours is of great importance, like in situations when considering the treatment of glioblastoma patients with immunotherapeutic agents.

Decreasing ADHD phenotypic heterogeneity: searching for neurobiological underpinnings of the restrictive inattentive phenotype.

During the process of developing the DSM-5, a new phenotype of ADHD was proposed-the ADHD restrictive inattentive presentation (ADHD-RI), describing subjects with high endorsement of inattentive symptoms and a low level of hyperactivity. However, this phenotype was not included in the DSM-5 because of the lack of robust neurobiological data. We aimed to assess the specific neurobiological underpinnings of individuals presenting ADHD-RI. We compared a sample of 301 subjects (101 ADHD-Combined; 50 ADHD-RI; 50 ADHD predominantly inattentive type and 100 typically developing subjects) aged 8-15 years, using a complete neuropsychological battery, molecular genetic data (DRD4 and DAT1 most studied polymorphisms) and functional MRI during a Go-No/Go task. Subjects with ADHD-RI had a significantly different neuropsychological profile compared with the other groups, including lower psychomotor speeds, longer reaction times and the worst overall performance in the global neurocognitive index. The proportion of subjects with the presence of DRD4-7 repeat allele was significantly higher in ADHD-RI. The fMRI data suggested that more attention-related posterior brain regions (especially temporo-occipital areas) are activated in ADHD-RI during both Go and No-Go cues compared to TD controls and ADHD predominantly inattentive type. ADHD-RI may represent a different phenotype than other types of ADHD. In addition, our results suggest that reducing the phenotypic heterogeneity may aid in the search for the neurobiological underpinnings of ADHD.

MicroRNA-520a-5p displays a therapeutic effect upon chronic myelogenous leukemia cells by targeting STAT3 and enhances the anticarcinogenic role of capsaicin.

Aberrant expression profiles of microRNAs (miRNAs) have been previously demonstrated for having essential roles in a wide range of cancer types including leukemia. Antiproliferative or proapoptotic effects of capsaicin have been reported in several cancers. We aimed to study miRNAs involved in the Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway in chronic myeloid leukemia cell model and the effects of the capsaicin treatment on cell proliferation and miRNA regulation. miR-520a-5p expression was extremely downregulated in capsaicin-treated cells. Repressing the level of miR-520a-5p by transient transfection with specific miRNA inhibitor oligonucleotides resulted in induced inhibition of proliferation in leukemic cells. According to bioinformatics analysis, STAT3 messenger RNA was predicted as a putative miR-520a-5p target; which was confirmed by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) and Western blot analysis. Cell proliferation inhibition was enhanced upon knockdown of STAT3 by RNA interference applications, but when miR-520a-5p inhibitor was additionally transfected onto STAT3 silenced cells, cell viability was dramatically decreased in leukemia cells. Finally, we observed the effects of capsaicin following miR-520a-5p inhibitor transfection upon cell proliferation, apoptosis, and STAT3 expression levels. We determined that, downregulation of miR-520a-5p affected the proliferation inhibition enhanced by capsaicin and reduced STAT3 mRNA and protein expression levels and increased apoptotic cell number. In summary, miR-520a-5p displays a therapeutic effect by targeting STAT3 and impacting the anticancer effects of capsaicin; whereas capsaicin, potentially through the miR-520a-5p/STAT3 interaction, induces apoptosis and inhibits K562 leukemic cell proliferation with need of further investigation.

Bortezomib induces apoptosis by interacting with JAK/STAT pathway in K562 leukemic cells.

In the current study, we aimed to identify the cytotoxic and apoptotic effects of bortezomib (BOR) on human K562 chronic myelogenous leukemia cells and to evaluate the potential roles of Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway members STAT3, STAT5, and JAK2 on BOR-induced cell death of leukemic cells. Cell viability was assessed via trypan blue dye exclusion test, and cytotoxicity of the BOR-treated cells was conducted by 2,3-bis(2-methoxy-4-nitro-5-sulphophenyl)-2H-tetrazolium-5-carboxanilide inner salt (XTT) assay. The relative messenger RNA (mRNA) expression levels of STAT3, STAT5A, STAT5B, and JAK2 were analyzed by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). On the other hand, their protein expression levels were detected by western blot method. The obtained results indicated that BOR treatment reduced cell viability and induced leukemic cell apoptosis in a dose- and time-dependent manner as compared to untreated control cells. While mRNA expression levels of STAT5A, STAT5B, and STAT3 were significantly reduced following BOR treatment when compared to untreated controls, it had no effect upon JAK2 mRNA expression. As for protein levels, STAT expressions were downregulated after BOR treatment especially at 72nd and 96th hours. Our results pointed out that BOR treatment had a significant potential of being an anticancer agent for chronic myelogenous leukemia therapy, and this effect could be due to the expressional downregulations of JAK/STAT pathway members.

Suppression of STAT3 by chemically modified siRNAs increases the chemotherapeutic sensitivity of parental and cisplatin-resistant non-small cell lung cancer cells.

PURPOSE: Increased activation of the JAK-STAT signaling pathway is frequently observed in several primary cancers as well as cancer cell lines. Thus, targeting JAK-STAT pathway components by different molecular-biologic approaches in the search for new anticancer therapies has become widespread and resulted in encouraging outcomes. In this study, the effects of chemically modified anti-STAT3 small interfering (si)RNAs on cell viability, proliferation and apoptosis of parental and cisplatin resistant non-small cell lung cancer (NSCLC) cells were investigated with the aim to provide a new therapeutic strategy for overcoming cisplatin resistance in lung cancer. METHODS: The parental NSCLC cell line Calu1 and its cisplatin- resistant subline CR-Calu1 were used to study the effects of STAT3 suppression with chemically modified anti-STAT3 siRNAs. STAT3 gene and protein expressions were analyzed by real-time (RT) quantitative (q) PCR and Western blot, respectively. Apoptosis was evaluated by Caspase-3 activity and cell death assays. RESULTS: STAT3 messenger (m)RNA and protein expression were significantly increased in CR-Calu1 cells and suppressing its expression with specific siRNAs increased the rate of apoptosis through Caspase-3 activation. STAT3 suppression also significantly increased cisplatin sensitivity of Calu1 and CR-Calu1 cells after transfection with STAT3 siRNAs. CONCLUSIONS: NSCLC cells could be sensitized to cisplatin by targeting STAT3 with chemically modified siRNAs together, a fact which was accompanied with increased apoptosis.

Repression of STAT3, STAT5A, and STAT5B expressions in chronic myelogenous leukemia cell line K-562 with unmodified or chemically modified siRNAs and induction of apoptosis.

Signal transducers and activators of transcription (STAT) proteins are latent cytoplasmic transcription factors that affect several cellular processes including cell growth, proliferation, differentiation, and survival. Following phosphorylation, STATs are activated, and their upregulated expressions increase in malignancies with playing a role in the development of leukemia. In this study, transfection of K-562 cells with either unmodified or chemically modified anti-STAT3, -STAT5A, -STAT5B siRNAs for duration of 12 days, determining gene silencing at mRNA and protein levels, evaluating apoptosis rate, and detecting JAK/STAT pathway members' gene expression profiles via array method were aimed. Quantitative RT-PCR and Western blot assays indicated that STAT expressions were downregulated both at mRNA and protein levels, and TUNEL assay showed that leukemic cell apoptosis was induced due to inhibition of STATs. Array analysis resulted with decreases in signal transducer, phosphorylation inducer, and oncogene expressions, whereas increased expressions in STAT inhibitor and apoptosis inducer genes were observed. These results point out that siRNA application could constitute a new and alternative curative method for supporting therapy of CML-diagnosed patients in the future.

Role of 14-3-3σ in resistance to cisplatin in non-small cell lung cancer cells.

The efficacies of chemotherapeutic agents are often limited by side effects and acquired drug resistance. We have investigated whether the differential expression pattern of 14-3-3σ affects cisplatin response in non-small cell lung cancer cell lines. Two pairs of parental/cisplatin resistant cell lines (A549/CRA549 and Calu1/CR-Calu1) and clinical lung cancer biopsy samples were analysed for 14-3-3σ expression. Cell viability was assessed by WST assay; and 14-3-3σ expression was suppressed by siRNA transfection. 14-3-3σ mRNA expression increased in CR-A549 and CR-Calu1 compared with their cisplatin-sensitive parental A549 and Calu1 cell lines. But when 14-3-3σ expression was suppressed, elevated cisplatin response was seen in A549 and CR-Calu1 cell lines. Increased 14-3-3σ expression might also account for reduced cisplatin response in vivo, since, 14-3-3σ expression in clinical biopsy samples obtained from lung cancer patients undergoing cisplatin-based chemotherapy significantly higher in the non-responder compared with the responder group. We therefore propose that increased 14-3-3σ expression is correlated with cisplatin response in non-small cell lung cancer cells; monitoring its expression might become useful in the future in predicting poor outcome to cisplatin treatment and/or the verification of acquired cisplatin resistance in lung cancer patients.

Two cases with hypereosinophilic syndrome shown with real-time PCR and responding well to imatinib treatment.

The aim of this work was to report two cases of hypereosinophilic syndrome (HES). FIP1L1-PDGFRA fusion was assessed with two protocols at RNA level. The fusion transcript was found positive at the RNA level with both PCR methods in two cases. In this study, the efficiency of imatinib treatment and a dramatic response in two HES cases with multisystemic involvement showing the characteristics of a chronic myeloproliferative disease were presented. Both cases showed complete responses confirming that imatinib mesylate treatment could be successful even in patients with advanced HES having myeloproliferative disease.

Analysis of Fat Graft Survival and Platelet-Rich Plasma Effects: The Transcriptomic Differences.

INTRODUCTION: Fat graft survival has been studied numerously but has not gone beyond hypothetical solutions. The molecular changes in survival of standard fat grafts and enhanced survival by platelet-rich plasma (PRP) are compared in this study to reveal the etiology that causes the loss of fat grafts after transplantation. MATERIALS AND METHODS: A New Zealand rabbit's inguinal fat pads were excised and divided into three groups: Sham, Control (C), and PRP. Each weighing 1 g, C and PRP fat were placed into the bilateral parascapular area of the rabbit. After 30 days, the remaining fat grafts were harvested and weighed (C = 0.7 g, PRP = 0.9 g). All three specimens were put into transcriptome analysis. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes Analysis were done to compare the genetic pathways between the specimens. RESULTS: Transcriptome analysis showed similar differential expressions in Sham vs. PRP and Sham vs. C comparisons, indicating the dominance of the cellular immune response in both C and PRP specimens. C and PRP comparison resulted in inhibited migration and inflammation pathways in PRP. CONCLUSION: Fat graft survival is more related to immune responses than any other physiological process. PRP enhances survival by attenuating cellular immune reactions.

Molecular dynamic simulation and functional analysis of pathogenic PTEN mutations in glioblastoma.

PTEN, a dual-phosphatase and scaffold protein, is one of the most commonly mutated tumour suppressor gene across various cancer types in human. The aim of this study therefore was to investigate the stability, structural and functional effects, and pathogenicity of 12 missense PTEN mutations (R15S, E18G, G36R, N49I, Y68H, I101T, C105F, D109N, V133I, C136Y, R173C and N276S) found by next generation sequencing of the PTEN gene in tissue samples obtained from glioblastoma patients. Computational tools and molecular dynamic simulation programs were used to identify the deleterious effects of these mutations. Furthermore, PTEN mRNA and protein expression levels were evaluated by qRT-PCR, Western Blot, and immunohistochemistry staining methods. Various computational tools predicted strong deleterious effects for the G36R, C105F, C136Y and N276S mutations. Molecular dynamic simulation revealed a significant decrease in protein stability for the Y68H and N276S mutations when compared with the wild type protein; whereas, C105F, D109N, V133I and R173C showed partial stability reduction. Significant residual fluctuations were observed in the R15S, N49I and C136Y mutations and radius of gyration graphs revealed the most compact structure for D109N and least for C136Y. In summary, our study is the first one to show the presence of PTEN E18G, N49I, D109N and N276S mutations in glioblastoma patients; where, D109N is neutral and N276S is a damaging and disease-associated mutation.Communicated by Ramaswamy H. Sarma.

Cisplatin resistance induced by decreased apoptotic activity in non-small-cell lung cancer cell lines.

We have investigated defective steps in apoptosis that might account for the development of resistance. For this purpose, A549 and Calu1 NSCLC (non-small-cell lung cancer) cell lines were treated with cisplatin to obtain resistant sub-lines. Gene expression profiles and the phosphorylation status of the BAD (Bcl-2/Bcl-XL-antagonist, causing cell death) protein were determined for each cell line. Cell death and cytochrome c release were analysed after treating cell lines with their appropriate cisplatin doses. Gene expression of BAD, Bid, caspases 4 and 6 were clearly decreased in the resistant cell lines, and the differential phosphorylation status of BAD also seemed to play a role in the development of cisplatin resistance. Since this is a new cisplatin-resistant Calu1 cell line, it is noteworthy that DNA fragmentation, apoptotic cell ratio and cytochrome c levels were most decreased in the CR-Calu1 cell line.

Molecular Evaluation of t(14;18)(bcl-2/IgH) Translocation in Follicular Lymphoma at Diagnosis Using Paraffin-Embedded Tissue Sections.

OBJECTIVE: Follicular lymphoma (FL) is one of the most common lymphomas, and is characterized by t(14;18)(q32;q21) in more than 80% of patients. The aim of this study was to determine the rate of t(14;18) positivity based onthe detection of mbr or mcr in paraffin-embedded tissue samples. MATERIAL AND METHODS: The study included 32 paraffin-embedded tissue samples collected from 32 consecutive FL patients that were diagnosed and followed-up at our hospital between 1999 and 2006. The MBR breakpoint wasidentified based on real-time PCR using a LightCycler v.2.0 t(14;18) Quantification Kit (MBR), multiplex PCR, and seminestedPCR. To identify the mcr breakpoint, real-time PCR was performed using specific primers and the FastStart DNAMaster SYBR Green I Kit. To detect t(14;18) via fluorescence in situ hybridization (FISH) nuclei from paraffin-embeddedtissue sections were extracted and used together with LSI IgH (immunoglobulin heavy chain) (spectrum green)/bcl-2(B-cell leukemia-lymphoma 2) (spectrum orange) probes. RESULTS: The DNA and nuclei isolation success rate for B5 formalin-fixed, paraffin-embedded tissue sections (n = 12)was 42% and 33%, respectively, versus 95% and 60%, respectively, for 20 tissue sections fixed in formalin only. In all,24 paraffin-embedded tissue sections were analyzed and mbr positivity was observed in the DNA of 82.14% via seminested PCR, in 53.57% via multiplex PCR, and in 28.57% via real-time PCR. We did not detect mcr rearrangementin any of the samples. In all, 15 of 16 patients (93.75%) whose nuclei were successfully isolated were observed to bet(14;18) positive via the FISH method. CONCLUSION: Semi-nested PCR and FISH facilitated the genetic characterization of FL tumors. As such, FISH and PCR complement each other and are both essential for detecting t(14;18) translocation.

Functional roles of miR-625-5p and miR-874-3p in the progression of castration resistant prostate cancer.

AIMS: Androgen receptor (AR) signaling is important in normal prostate and prostate tumor tissues. Thus, the new therapeutic strategies targeting ARs may also be important for treatment of prostate cancer (PC) and its biology. The studies have shown that miRNAs to be dysregulated in PC progression. Therefore, in the present study, differentially expressed miRNAs that predictively target the ARs were identified and investigated by in silico analysis. MAIN METHODS: Cellular proliferation, qPCR, western blot and apoptosis assays were performed to investigate the molecular mechanism of the selected miRNAs in the PC cells. KEY FINDINGS: In our miRNA qPCR study, several miRNAs were found to be differentially regulated in castration resistant prostate cancer (CRPC) cells (LNCaP-Abl and LNCaP-104R2) compared with androgen dependent (AD) cells (LNCaP). The expression levels of miR-625-5p and miR-874-3p were significantly increased in LNCaP-Abl (2.62-fold, p = 0.0002; 4.00-fold, p = 0.00002, respectively) and LNCaP-104R2 (2.44-fold, p = 0.0455; 3.77-fold, p = 0.0383, respectively) compared with AD cells. The expression levels of AR and prostate specific antigen were increased in PC cells compared with AD cells. Furthermore, transfection of PC cells with anti-miRs suppressed their proliferation and AR protein levels (p < 0.05). SIGNIFICANCE: Several differentially regulated miRNAs were identified in CRPC cells, including miR-625-5p and miR-874-3p that are potentially involved in PC progression. These results may provide novel insights into the molecular mechanism underlying CRPC cells and miRNA applications may constitute a new and alternative method to prevent development of CRPC cells in the future.

A floating thrombus in sinus of valsalva complicated with cardiogenic shock in a patient with plasminogen activator inhibitor 1 4G/5G polymorphism.

Thrombus in sinus of Valsalva is unusual reason for acute myocardial infarction. We demonstrated a case with floating thrombus in sinus of Valsalva obstructing the right coronary ostium intermittently, and causing cardiogenic shock. The patient was diagnosed with multiplane transesophageal echocardiography and treated successfully with surgical removal of mass. A homozygote polymorphism of plasminogen activator inhibitor (PAI) 1 4G/5G was found. This is the first report demonstrating a patient with PAI 1 polymorphism and thrombus of Valsalva complicated with cardiogenic shock.

Factor V G1691A (Leiden) and prothrombiG20210A gene mutation status, and thrombosis in patients with chronic myeloproliferative disorders.

OBJECTIVE: The aim of this study was to examine Factor V G1691A (Leiden) (FVL) and prothrombin G20210A (PT) gene mutation status, and their relationship with thrombosis in patients with chronic myeloproliferative disorders (CMPDs). METHODS: The study included 160 patients with a CMPD that were regularly followed-up between 1993 and 2009. FVL and PT mutation status was established based on blood samples analyzed via PCR using specific primers. RESULTS: The frequency of FVL and PT mutation was 12.5% and 4.4%, respectively. In total, 27 episodes of thrombosis occurred in 24 (15%) of the patients, and there wasn't an association between the observed thrombotic events, and FVL or PT mutations. Hepatic vein thrombosis was noted in 3 patients that had FVL mutation, of which 1 also had PT mutation. CONCLUSION: We did not observe a relationship between thrombosis, and FVL or PT mutations in CMPD patients; however, 3 of the patients that had hepatic vein thrombosis also had FVL mutation. Larger studies are needed to more clearly determine if all CMPD patients with hepatic vein thrombosis need be investigated for FVL and PT mutation.

Effects of the dopamine transporter gene on neuroimaging findings in different attention deficit hyperactivity disorder presentations.

Attention-Deficit/Hyperactivity Disorder (ADHD) is a phenotipically and neurobiologically heterogeneous disorder. Deficiencies at different levels in response inhibition, differences in dopamine transporter genotype (DAT1) and various symptomatic presentations contribute to ADHD heterogeneity. Integrating these three aspects into a functional neuroimaging research could help unreval specific neurobiological components of more phenotipically homogeneous groups of patients with ADHD. During the Go-NoGo trial, we investigated the effect of the DAT1 gene using 3 T MRI in 72 ADHD cases and 24 (TD) controls that typically developed between the ages 8 and 15 years. In the total ADHD group, DAT1 predicted homozygosity for the 10R allele and hypoactivation in the anterior cingulate cortex and paracingulate cortex. There were no significant activation differences between DAT1 10R/10R homozygotes and 9R carriers in TD controls. Subjects with predominantly inattentive ADHD (ADHD-I) presentation with DAT1 10R/10R homozygous reduced neuronal activation during Go trial particularly in the frontal regions and insular cortex, and in the parietal regions during NoGo trial (brain regions reported as part of Default Mode Network- DMN). Additionally, DAT1 10R/10R homozygousness was associated with increased occipital zone activation during only the Go trial in the ADHD combined presentation (ADHD-C) group. Our results point the three main findings: 1) The DAT1 gene is 10R homozygous for differentiated brain activation in ADHD cases but not in the TD controls, supporting the DAT1 gene as a potential marker for ADHD, 2) The relationship between the DAT1 gene and the occipital regions in ADHD-C group which may reflect compensatory mechanisms, 3) The relationship between DAT1 gene and the reduced DMN suppression for 9R carriers probabaly stems from the ADHD-I group.

DRD4 genotyping may differentiate symptoms of attention-deficit/hyperactivity disorder and sluggish cognitive tempo.

OBJECTIVE: Studies to reduce the heterogeneity of attention-deficit/hyperactivity disorder (ADHD) have increased interest in the concept of sluggish cognitive tempo (SCT). The aim of this study was to investigate if the prevalence of two variable-number tandem repeats (VNTRs) located within the 3'-untranslated region of the DAT1 gene and in exon 3 of the dopamine D4 receptor (DRD4) gene differ among four groups (31 subjects with SCT but no ADHD, 146 individuals with ADHD but no SCT, 67 subjects with SCT + ADHD, and 92 healthy controls). METHODS: We compared the sociodemographic profiles, neurocognitive domains, and prevalence of two VNTRs in SCT and ADHD subjects versus typically developing (TD) controls. RESULTS: The SCT without ADHD group had a higher proportion of females and lower parental educational attainment. Subjects in this group performed worse on neuropsychological tests, except for psychomotor speed and commission errors, compared to controls. However, the ADHD without SCT group performed significantly worse on all neuropsychological domains than controls. We found that 4R homozygosity for the DRD4 gene was most prevalent in the ADHD without SCT group. The SCT without ADHD group had the highest 7R allele frequency, differing significantly from the ADHD without SCT group. CONCLUSION: The 7R allele of DRD4 gene was found to be significantly more prevalent in SCT cases than in ADHD cases. No substantial neuropsychological differences were found between SCT and ADHD subjects.

Non ST-segment elevation myocardial infarction in patient with essential thrombocythemia.

A 68-year-old woman presented with acute chest pain and a greatly increased platelet count. Cardiac catheterization revealed subtotal occlusion and a thrombus-like filling defect in the right coronary artery. The patient was successfully treated with intravenous tirofiban. Essential thrombocythemia was diagnosed based on bone marrow findings, clinical presentation and laboratory analysis. The relationship between intracoronary thrombus and essential thrombocythemia is discussed.

Apolipoprotein E gene polymorphism and polycystic ovary syndrome patients in Western Anatolia, Turkey.

PURPOSE: Dyslipidemia, cardiovascular disease and hypertension are more frequently seen in patients with PCOS than in normal patients. We aimed at evaluating the distribution of Apo E alleles that can influence cardiovascular risk of the PCOS patients and control subjects. METHODS: In this study, 129 young women with PCOS and 91 healthy women were included. In all subjects we performed hormonal, biochemical and Apo E genetic analysis. RESULTS: The Apo E3 allele was found at a significantly higher frequency in the PCOS patient group compared with the control group. The Apo E2 allele was found at a significantly higher frequency in the control group compared with the patient group with PCOS. CONCLUSIONS: Although there were genotype and allele differences between control and patient groups in this study, no statistically significant change was determined in lipid and other cardiovascular risk factors in connection with allele and genotype.

Cisplatin ototoxicity in children: risk factors and its relationship with polymorphisms of DNA repair genes ERCC1, ERCC2, and XRCC1.

PURPOSE: We aimed to investigate the cisplatin-related hearing toxicity and its possible relationship with polymorphic variants in DNA repair genes, ERCC1, ERCC2, and XRCC1. METHODS: Fifty patients treated with cisplatin in the past were included in the study. There were 29 females and 21 males; mean age 13.4 ± 6.0 years). The polymorphism in DNA repair genes was studied using primer and probes in Light Cycler device after DNA isolation was carried out with PCR technique. The polymorphisms and clinical risk factors were evaluated using Chi square test and logistic regression modelling. RESULTS: The patients had hearing loss in 44%. For ERCC1 gene, the patients with hearing loss had 50% of GG (wild type), 40.9% of AG and 9.1% of AA genotypes, while the patients without hearing loss had 28.6% of GG, 53.5% of AG, and 17.9% of AA genotypes. For ERCC2 gene, the patients with hearing loss had 18.2% of GG (wild type), 40.9% of TG, and 40.9% of TT genotypes, while the patients without hearing loss had 10.7% of GG 39.3% of TG, and 50% of TT genotypes. For XRCC1 gene, the patients with hearing loss had 18.2% of CC (wild type), 59.1% of CT, and 22.7% of TT genotypes, while the patients without hearing loss had 35.7% of CC, 50% of CT, and 14.3% of TT genotypes. There was no statistically significant association among the groups (p = 0.24). CONCLUSION: We did not find a relationship between DNA repair gene polymorphisms and hearing toxicity of cisplatin.