Functional evaluation of germline TP53 variants identified in Brazilian families at-risk for Li-Fraumeni syndrome.

Germline TP53 pathogenic variants can lead to a cancer susceptibility syndrome known as Li-Fraumeni (LFS). Variants affecting its activity can drive tumorigenesis altering p53 pathways and their identification is crucial for assessing individual risk. This study explored the functional impact of TP53 missense variants on its transcription factor activity. We selected seven TP53 missense variants (c.129G > C, c.320A > G, c.417G > T, c.460G > A, c,522G > T, c.589G > A and c.997C > T) identified in Brazilian families at-risk for LFS. Variants were created through site-directed mutagenesis and transfected into SK-OV-3 cells to assess their transcription activation capabilities. Variants K139N and V197M displayed significantly reduced transactivation activity in a TP53-dependent luciferase reporter assay. Additionally, K139N negatively impacted CDKN1A and MDM2 expression and had a limited effect on GADD45A and PMAIP1 upon irradiation-induced DNA damage. Variant V197M demonstrated functional impact in all target genes evaluated and loss of Ser15 phosphorylation. K139N and V197M variants presented a reduction of p21 levels after irradiation. Our data show that K139N and V197M negatively impact p53 functions, supporting their classification as pathogenic variants. This underscores the significance of conducting functional studies on germline TP53 missense variants classified as variants of uncertain significance to ensure proper management of LFS-related cancer risks.

Primary hepatic pleomorphic liposarcoma: Case report and literature review.

Primary hepatic liposarcoma is an extremely rare malignant tumour derived from adipocytes and is part of the group of mesenchymal tumours. We present the case of a 43-year-old Hispanic male patient with a pleomorphic hepatic liposarcoma and absence of MDM2 gene amplification. Two years and six months after surgery, the patient is asymptomatic. The present case is the first report of this entity with positive immunohistochemical testing for p16, p53, S100, vimentin and absence of MDM2 gene amplification.

MDM2 Regulation of HIF Signaling Causes Microvascular Dysfunction in Hypertrophic Cardiomyopathy.

BACKGROUND: Microvasculature dysfunction is a common finding in pathologic remodeling of the heart and is thought to play an important role in the pathogenesis of hypertrophic cardiomyopathy (HCM), a disease caused by sarcomere gene mutations. We hypothesized that microvascular dysfunction in HCM was secondary to abnormal microvascular growth and could occur independent of ventricular hypertrophy. METHODS: We used multimodality imaging methods to track the temporality of microvascular dysfunction in HCM mouse models harboring mutations in the sarcomere genes Mybpc3 (cardiac myosin binding protein C3) or Myh6 (myosin heavy chain 6). We performed complementary molecular methods to assess protein quantity, interactions, and post-translational modifications to identify mechanisms regulating this response. We manipulated select molecular pathways in vivo using both genetic and pharmacological methods to validate these mechanisms. RESULTS: We found that microvascular dysfunction in our HCM models occurred secondary to reduced myocardial capillary growth during the early postnatal time period and could occur before the onset of myocardial hypertrophy. We discovered that the E3 ubiquitin protein ligase MDM2 (murine double minute 2) dynamically regulates the protein stability of both HIF1α (hypoxia-inducible factor 1 alpha) and HIF2α (hypoxia-inducible factor 2 alpha)/EPAS1 (endothelial PAS domain protein 1) through canonical and noncanonical mechanisms. The resulting HIF imbalance leads to reduced proangiogenic gene expression during a key period of myocardial capillary growth. Reducing MDM2 protein levels by genetic or pharmacological methods normalized HIF protein levels and prevented the development of microvascular dysfunction in both HCM models. CONCLUSIONS: Our results show that sarcomere mutations induce cardiomyocyte MDM2 signaling during the earliest stages of disease, and this leads to long-term changes in the myocardial microenvironment.

Association of rs1570360 and rs2010963 in VEGF and rs2279744 in the MDM2 gene with Recurrent Implantation Failure in Iranian Women.

OBJECTIVE: The embryo implantation includes a complex sequence of signaling events, comprising numerous molecular mediators, such as ovarian hormones, cytokines, adhesion molecules and, growth factors. One of the critical factors in angiogenesis is the vascular endothelial growth factor (VEGF). The VEGF plays a pivotal role in embryonic development, decidua vascularization and placental angiogenesis. Furthermore, the P53 gene and its negative regulator, murine double minute 2 (MDM2), are major players in reproductive processes. This study aimed to assess the association of polymorphisms of the VEGF and the MDM2 genes with idiopathic recurrent implantation failure. METHODS: We genotyped 60 women with previous idiopathic recurrent implantation failures and 60 fertile women as controls. Restriction Fragment Length Polymorphism (RFLP) and Sanger sequencing were used for genotyping the rs2010963 and the rs1570360 polymorphisms in VEGF; and the rs2279744 in MDM2 genes. RESULTS: Results indicated a higher frequency of the VEGF rs1570360 AA genotype and A allele in patients with a history of idiopathic implantation failure [OR=6.4 (1.22 - 33.64), p-value=0.02)]. However, the frequency of VEGF +405 G/C and MDM2 SNP309 T/G [(OR=3 (0.5 - 16) p-value=0.2, OR=1.18 (0.3 - 3.7) p-value=0.7, respectively)] genotypes were not significantly different between cases and controls. CONCLUSIONS: The VEGF polymorphism may influence embryo implantation and the VEGF rs1570360 AA genotype may predispose to the risk of recurrent implantation failure after IVF.

Long intergenic non-coding RNA-p21 is associated with poor prognosis in chronic lymphocytic leukemia.

BACKGROUND: Long non-coding RNAs (LncRNAs) are RNA transcripts longer than 200 nucleotides. They are new players in transcriptional regulation and cancer research. LincRNA-p21 is a p53-regulated lncRNA involved in the p53 transcriptional network. It has an important role in regulating cellular proliferation and apoptosis. Chronic lymphocytic leukemia is derived by a typical defect in apoptosis and characterized by clonal proliferation and accumulation of mature B cells. The aim of the present study was to assess the expression pattern of the lincRNA-p21 and investigate its potential role as a new prognostic marker in CLL. METHODS: The study was conducted on 80 newly diagnosed CLL patients and 80 age- and sex-matched controls. The analysis of LincRNA-p21 and the p53 downstream proapoptotic target genes (MDM2, PUMA, BAX, and NOXA) was performed by real-time PCR. The cytogenetic abrasions and expression of ZAP70 and CD38 were detected by FISH and Flow cytometry, respectively. RESULTS: LincRNA-p21 was significantly downregulated in CLL patients compared to controls. The downstream proapoptotic targets were significantly downregulated in CLL patients and positively correlated with lincRNA-p21. Low expression of lincRNA-p21 was associated with poor prognostic markers (advanced stages of CLL, del 17p13, ZAP70, and CD38 expression), failure of complete remission, shorter progression free survival, and overall survival. Low lincRNA-p21 expression was independently prognostic for shorter time to treatment. CONCLUSION: Low expression of lincRNA-p21 demarcates a more aggressive form of CLL with poor prognosis. Therefore, it could be considered as a new prognostic marker to predict disease outcome in CLL.

Anti-Cancer Tumor Cell Necrosis of Epithelial Ovarian Cancer Cell Lines Depends on High Expression of HDM-2 Protein in Their Membranes.

OBJECTIVE: Patients with epithelial ovarian cancers experience the highest fatality rates among all gynecological malignancies which require development of novel treatment strategies. Tumor cell necrosis was previously reported in a number of cancer cell lines following treatment with a p53-derived anti-cancer peptide called PNC-27. This peptide induces necrosis by transmembrane pore formation with HDM-2 protein that is expressed in the cancer cell membrane. We aimed to extend these studies further by investigating expression of membrane HDM-2 protein in ovarian cancer as it relates to susceptibility to PNC-27. PROCEDURES: Herein, we measured HDM-2 membrane expression in two ovarian cancer cell lines (SKOV-3 and OVCAR-3) and a non-transformed control cell line (HUVEC) by flow cytometric and western blot analysis. Immunofluorescence was used to visualize colocalization of PNC-27 with membrane HDM-2. Treatment effects with PNC-27 and control peptide were assessed using a MTT cell proliferation assay while direct cytotoxicity was measured by lactate dehydrogenase (LDH) release and induction of apoptotic markers; annexin V and caspase-3. RESULTS: HDM-2 protein was highly expressed and frequently detected in the membranes of SKOV-3 and OVCAR-3 cells; a prominent 47.6 kDa HDM-2 plasma membrane isoform was present in both cell lines whereas 25, 29, and 30 kDa isoforms were preferentially expressed in OVCAR-3. Notably, PNC-27 colocalized with HDM-2 in the membranes of both cancer cell lines that resulted in rapid cellular necrosis. In contrast, no PNC-27 colocalization and cytotoxicity was observed with non-transformed HUVEC demonstrating minimal expression of membrane HDM-2. CONCLUSIONS: Our results suggest that HDM-2 is highly expressed in the membranes of these ovarian cancer cell lines and colocalizes with PNC-27. We therefore conclude that the association of PNC-27 with preferentially expressed membrane HDM-2 isoforms results in the proposed model for the formation of transmembrane pores and epithelial ovarian cancer tumor cell necrosis, as previously described in a number of solid tissue and hematologic malignancies.

Anti-tumor activity of the MDM2-TP53 inhibitor BI-907828 in dedifferentiated liposarcoma patient-derived xenograft models harboring MDM2 amplification.

PURPOSE: Dedifferentiated liposarcoma (DDLPS) is a soft tissue malignancy characterized by amplification of the mouse double minute 2 homolog (MDM2) gene. MDM2 is a negative regulator of tumor protein 53 (TP53). We tested the in vivo efficacy of BI-907828, a small molecule inhibitor of the MDM2-TP53 interaction, in two DDLPS patient-derived xenografts (PDX). METHODS: Partially immunodeficient mice were bilaterally engrafted with UZLX-STS3 (n = 24) and UZLX-STS5 (n = 24) human DDLPS tissue harboring MDM2 amplifications. Mice were grouped as follows: (a) vehicle (0.5% hydroxyethylcellullose) 10 ml/kg daily per os (p.o.); (b) doxorubicin 5 mg/kg weekly intraperitoneally (i.p.); (c) BI-907828 2.5 mg/kg daily p.o. and (d) BI-907828 10 mg/kg daily p.o. The treatment lasted for 15 days, all mice treated with BI-907828 were followed for 37 days post-treatment. Efficacy was assessed by tumor volume and histopathological evaluation. RESULTS: The 15-day treatment with 2.5 mg/kg and 10 mg/kg BI-907828 significantly inhibited tumor growth in UZLX-STS5 and -STS3 (p < 0.0001 compared to control for both models). All UZLX-STS5 and -STS3 tumors treated with BI-907828 decreased in size during treatment, and BI-907828-treated UZLX-STS5 tumors even disappeared completely. During the follow-up period, no tumor regrowth was observed in the UZLX-STS5 model and both doses of BI-907828 led to a pathological complete response, whereas a dose-dependent regrowth was seen in the UZLX-STS3 model. CONCLUSION: BI-907828 showed significant anti-tumor activity in DDLPS PDX harboring MDM2 amplifications, providing a strong rationale for early clinical testing of BI-907828 in a DDLPS patient population.

Li-Fraumeni syndrome heterogeneity.

Clinical variability is commonly seen in Li-Fraumeni syndrome. Phenotypic heterogeneity is present among different families affected by the same pathogenic variant in TP53 gene and among members of the same family. However, causes of this huge clinical spectrum have not been studied in depth. TP53 type mutation, polymorphic variants in TP53 gene or in TP53-related genes, copy number variations in particular regions, and/or epigenetic deregulation of TP53 expression might be responsible for clinical heterogeneity. In this review, recent advances in the understanding of genetic and epigenetic aspects influencing Li-Fraumeni phenotype are discussed.

Human amniotic membrane conditioned medium inhibits proliferation and modulates related microRNAs expression in hepatocarcinoma cells.

The placental stem cells have called the focus of attention for their therapeutic potential to treat different diseases, including cancer. There is plenty evidence about the antiproliferative, antiangiogenic and proapoptotic properties of the amniotic membrane. Liver cancer is the fifth cause of cancer in the world, with a poor prognosis and survival. Alternative treatments to radio- or chemotherapy have been searched. In this work we aimed to study the antiproliferative properties of the human amniotic membrane conditioned medium (AM-CM) in hepatocarcinoma cells. In addition, we have analyzed the regulation of pro and antiOncomiRs expression involved in hepatocarcinoma physiology. We have determined by 3H-thymidine incorporation assay that AM-CM inhibits DNA synthesis in HepG2 cells after 72 h of treatment. AM-CM pure or diluted at 50% and 25% also diminished HepG2 and HuH-7 cells viability and cell number. Furthermore, AM-CM induced cell cycle arrest in G2/M. When proliferation mechanisms were analyzed we found that AM-CM reduced the expression of both Cyclin D1 mRNA and protein. Nuclear expression of Ki-67 was also reduced. We observed that this CM was able to promote the expression of p53 and p21 mRNA and proteins, leading to cell growth arrest. Moreover, AM-CM induced an increase in nuclear p21 localization, observed by immunofluorescence. As p53 levels were increased, Mdm-2 expression was downregulated. Interestingly, HepG2 and HuH-7 cells treatment with AM-CM during 24 and 72 h produced an upregulation of antiOncomiRs 15a and 210, and a downregulation of proOncomiRs 206 and 145. We provide new evidence about the promising novel applications of human amniotic membrane in liver cancer.

Expression and purification of the recombinant full-length retinoblastoma protein and characterisation of its interaction with the oncoprotein HDM2.

Retinoblastoma (Rb) was the first tumour suppressor factor described, and it is dysfunctional in several types of cancers. Structurally, Rb is a very large, multifunctional protein organized in different domains connected by intrinsically disordered regions. Due to the complex structure of Rb, biochemical manipulation is difficult. The Rb protein has been implicated in many different cellular processes, such as the cell cycle control, senescence and even apoptosis. The activity of Rb is regulated by phosphorylation, and many different sites of phosphorylation have been described. However, the oncoprotein HDM2, can promote Rb degradation by the proteasome. This form of Rb regulation is largely unknown. Here we report the expression and purification of the full-length Rb protein and its phosphomimetic form, Rb(S567D), in a recombinant system. We also produced and purified the HDM2 protein and its phosphomimetic mutant, HDM2(S395D). The proteins interacted strongly when we used the phosphomimetic mutants, mimicking damaged DNA conditions. The expression of the proteins in E. coli allowed us to control the phosphorylation status of the proteins.

Comprehensive Genomic Profiling of Androgen-Receptor-Negative Canine Prostate Cancer.

Canine carcinomas have been considered natural models for human diseases; however, the genomic profile of canine prostate cancers (PCs) has not been explored. In this study, 14 PC androgen-receptor-negative cases, 4 proliferative inflammatory atrophies (PIA), and 5 normal prostate tissues were investigated by array-based comparative genomic hybridization (aCGH). Copy number alterations (CNAs) were assessed using the Canine Genome CGH Microarray 4 × 44K (Agilent Technologies). Genes covered by recurrent CNAs were submitted to enrichment and cross-validation analysis. In addition, the expression levels of TP53, MDM2 and ZBTB4 were evaluated in an independent set of cases by qPCR. PC cases presented genomic complexity, while PIA samples had a small number of CNAs. Recurrent losses covering well-known tumor suppressor genes, such as ATM, BRCA1, CDH1, MEN1 and TP53, were found in PC. The in silico functional analysis showed several cancer-related genes associated with canonical pathways and interaction networks previously described in human PC. The MDM2, TP53, and ZBTB4 copy number alterations were translated into altered expression levels. A cross-validation analysis using The Cancer Genome Atlas (TCGA) database for human PC uncovered similarities between canine and human PCs. Androgen-receptor-negative canine PC is a complex disease characterized by high genomic instability, showing a set of genes with similar alterations to human cancer.

p53 signaling pathway polymorphisms, cancer risk and tumor phenotype in TP53 R337H mutation carriers.

Li-Fraumeni and Li-Fraumeni-like syndrome (LFS/LFL) are clinically heterogeneous cancer predisposition syndromes characterized by diagnosis of early-onset and often multiple cancers with variable tumor patterns and incomplete penetrance. To date, the genetic modifiers described in LFS/LFL have been shown to map to either TP53 or its main negative regulator, MDM2. Additionally, all studies were focused on families with different TP53 germline mutations. Hence, in this study we explored the effect of the most studied polymorphisms of p53 pathway genes on clinical manifestations of individuals carrying the founder TP53 mutation R337H (n = 136) and controls (n = 186). Cancer-affected carriers had been diagnosed either with adrenocortical carcinoma (ACC, n = 29) or breast cancer (BC, n = 43). Allelic discrimation using TaqMan assay was used for genotyping MDM2 SNP 309 (rs2279744) as well as MDM4 (rs1563828) and USP7 (rs1529916) polymorphisms. We found significantly higher MDM2 SNP 309 GG genotype and G allele frequencies in the LFS cohort than in controls. Furthermore, median age at first diagnosis was earlier in MDM2 SNP309 GG carriers when compared to other genotypes for both cancers (ACC: age 1 vs. 2 years; BC: age 35 vs. 43 years, respectively), although not statistically different. The allelic and genotypic frequencies for all SNPs did not differ between cancer affected and unaffected carriers, neither between patients with ACC or BC. In conclusion, our results suggest that MDM2 SNP 309 may contribute to the LFL phenotype and also to an earlier age at diagnosis of ACC and BC cancer in carriers of the R337H founder mutation.

Association of the Del1518 Promoter (rs3730485) Polymorphism in the MDM2 Gene with Breast Cancer in a Mexican Population.

INTRODUCTION: The MDM2 gene plays an important role in tumorigenesis. The data on the Del1518 promoter polymorphism in the MDM2 gene have revealed associations with cancer. MATERIAL AND METHODS: We examined the role of the MDM2 Del1518 polymorphism through a comparison of the genotypes of 345 healthy Mexican women with those of 742 Mexican women with breast cancer (BC). RESULTS: The genotype frequencies of the MDM2 Del1518 polymorphism in controls and patients with BC were 64% and 55.5% for ins/ins, 32% and 31.5% for ins/del, and 4% and 13% for del/del, respectively. The obtained odds ratio (OR) was 3.26, with a 95% confidence interval (95% CI) of 1.86-5.72 and p=0.0001, for the del/del genotype. An association was evident when we examined the distribution of the del/del genotype in patients with elevated levels of transaminase SGPT (OR=2.268; 95% CI=1.40-3.65; p=0.0001). Additionally, we observed an association of the genotypes del/del - ins/del in menopausal patients with BC with the following characteristics: tobacco consumption (OR = 1.93, 95% CI = 1.07-3.4, p=0.025), pregnancy loss (OR=2.44, 95% CI=1.37-4.35, p=0.0024), obesity (I-IV) (OR=1.8, 95% CI=1.1-2.9, p= 0.018), and elevated serum glucose levels (OR=3.72, 95% CI=2.0-6.85, p=0.0001). CONCLUSIONS: The MDM2 Del1518 polymorphism was associated with BC susceptibility, particularly in menopausal patients with BC who reported tobacco consumption, pregnancy loss, obesity and high glucose levels in the analyzed Mexican population.

Inhibition of invasion and migration of prostate cancer cells by miRNA-509-5p via targeting MDM2.

Prostate cancer is a common malignancy of the male reproductive-urinary system. MDM2 is an oncogene, whose expression can be regulated by microRNA (miRNA). The present study investigated the expression and correlation of miRNA-509-5p and MDM2 to determine the mechanism of their function in invasion and migration of prostate cancer cells. RT-PCR was performed to detect the expression of miRNA-509-5p and MDM2 in tumor, tumor-adjacent, and normal tissues, obtained from prostate cancer patients, using the HGC-27 cell line as an in vitro model. Cultured HGC-27 cells were transfected with miRNA-509-5p mimics, miRNA-509-5p inhibitor, and mimic control. Expression levels of miRNA-509-5p and MDM2 were quantified by RT-PCR. Cell proliferation and invasion/migration were examined by the MTT and transwell assays, respectively. MiRNA-509-5p was significantly down-regulated in prostate cancer cells exhibiting high MDM2 mRNA levels. MiRNA mimic transfection elevated miRNA levels and suppressed MDM2 expression. With prolonged incubation time, the proliferation ratio and OD values of miRNA-509-5p mimic transfected cells decreased, along with decrease in cell migration and invasion. These results suggested that miRNA-509-5p negatively regulates MDM2 expression via targeting the 3'-UTR of genes. As a novel tumor suppressor, miRNA-509-5p in prostate cancer HGC-27 cells can suppress MDM2 expression and inhibit cell proliferation, invasion, and migration. Therefore, miRNA-509-5p could be used as a novel therapeutic agent in the treatment of prostate cancer.

Lipophyllodes of the breast. A reappraisal of fat-rich tumors of the breast based on 22 cases integrated by immunohistochemical study, molecular pathology insights, and clinical follow-up.

We have studied 22 cases of mammary lipophyllodes tumors (LPT), analyzing their clinicopathologic features along with available follow-up. All cases were tested for cytokeratins, S100 protein, and MDM2, and in selected cases for estrogen receptor, smooth muscle actin, bcl2, desmin, and myogenin. Patients were women aged 21 to 69 years (average, 45 years), and LPT size ranged from 1.6 to 30 cm (average, 9.7 cm). Microscopically, LPT segregated as follows: atypical lipoma-like tumor/well-differentiated liposarcoma (ALT/WDL), 8 cases; myxoid, 6; and pleomorphic/poorly differentiated/round cell, 8, including a case of dedifferentiated liposarcoma. Immunohistochemistry studies showed focal positive staining for S100 and CD34 in most ALT/WDL, and desmin and myogenin in 2 cases with evidence of rhabdomyoblastic differentiation. MDM2 positivity was focally seen in 1 case. Follow-up was available in 8 cases. Multiple recurrent tumors were seen in 2 patients, and metastatic disease to the lung was seen in 2 patients. In 4 patients with a follow-up between 2 and 15 years there was no evidence of recurrent or metastatic disease. Patients with ALT/WDL (2/2) were alive with no evidence of disease; 2 of 4 patients with myxoid liposarcoma component experienced tumor recurrence, whereas pleomorphic liposarcoma LPT pursued a less favorable course although only 1 patient died of the condition. Absence of MDM2 reactivity in most cases seems not as meaningful as in fatty tumors of somatic soft parts.

Clinical significance of TP53 (R72P) and MDM2 (T309G) polymorphisms in breast cancer patients.

INTRODUCTION: TP53 gene is the most frequently altered tumor suppressor gene in breast cancer. It has been observed that MDM2 plays a central role in regulating the TP53 pathway. This study aimed to investigate the role of TP53 Arg72Pro and MDM2 T309G polymorphisms in breast cancer patients. MATERIAL AND METHOD: The TP53 (Arg72Pro) and MDM2 (T309G) polymorphisms were studied in a hospital-based case control study by AS-PCR in 100 breast cancer patients and 100 healthy control subjects. RESULTS: It was observed that TP53 Arg72Pro polymorphism was significantly associated with breast cancer (χ (2) = 9.92, p = 0.007). A significantly increased breast cancer risk was associated with the Proline allele [odds ratio 1.84 (95 % CI: 1.22-2.77), risk ratio 1.34 (95 % CI: 1.11-1.63), p value 0.003], HER2/neu status (p = 0.01) and distant metastasis (p = 0.05). On the other hand, we have found a significant correlation between MDM2 (T309G) polymorphism with HER2/neu status (χ (2) = 11.14, p = 0.003) and distant metastasis (p value = 0.04). CONCLUSION: Our finding suggests that TP53 (Arg72Pro) polymorphism may play a significant role as risk factor for breast cancer in north Indian breast cancer patients. While MDM2 (T309G) polymorphism may not be directly associated with the risk of breast cancer occurrence in the same population, but it may play role in disease progression by triggering TP53.

EGFR, p53, IDH-1 and MDM2 immunohistochemical analysis in glioblastoma: therapeutic and prognostic correlation.

We studied 36 glioblastoma cases at HC-UNICAMP from 2008 to 2012 and classified the immunohistochemical distribution of the wild-type epidermal growth factor receptor (EGFR), mutated forms of p53 protein and isocitrate dehydrogenase-1 (IDH-1) and murine double protein 2 (MDM2). Immunostaining findings were correlated with clinical data and response to treatment (surgery, chemotherapy and radiotherapy). About 97% of the tumors were primary, most of them localized in the frontal lobe. Mean time free of clinical or symptomatic disease and free time of radiological disease were 7.56 and 7.14 months, respectively. We observed a significant positive correlation between expressions of p53 and MDM2, EGFR and MDM2. Clinical, radiological and overall survivals also showed a significant positive correlation. p53 staining and clinical survival showed a significant negative correlation. The current series provides clinical and histopathological data that contribute to knowledge on glioblastoma in Brazilians.

ASSOCIATION BETWEEN MURINE DOUBLE MINUTE 2 - T309G polymorphism and recurrence of hepatocellular carcinoma after surgical treatment.

BACKGROUND: Discovery and incorporation of biomarker panels to cancer studies enabled the understanding of genetic variation and its interference in carcinogenesis at molecular level. The potential association between single nucleotide polymorphism (SNP) 309 and increased development of tumors, such as hepatocellular carcinoma, has been subject to several studies. This is the first study on this association conducted in Brazil. METHODS: 62 cases of cirrhotic patients with hepatocellular carcinoma surgically treated by partial hepatectomy (HPT) or by liver transplantation (LTX) from 2000 to 2009 at Santa Casa Hospital Complex, in the city of Porto Alegre, were retrospectively analyzed. Tumor samples from surgical specimen were collected and prepared for study in paraffin blocks. RESULTS: Overall survival was 26.7 months in the HPT group and 62.4 months in the LTX group (P <0.01). Overall tumor recurrence was 66.7% in the HPT group (10/15) and 17% in the LTX group (8/47) (X²=13.602, P <0.01). Alpha-fetoprotein levels >200ng/mL, microvascular invasion and histological grade were associated with tumor recurrence (P <0.01). Recurrence rates in each surgical group and analysis of factors associated with tumor recurrence, when stratified for each genotypic pattern, were both not statistically significant. CONCLUSION: G/G genotype was not associated with tumor recurrence after surgical treatment and it did not show any correlation with other prognostic factors.

Effects of MDM2 promoter polymorphisms on the development of cervical neoplasia in a Southeastern Brazilian population.

We investigated the importance of two adjacent functional polymorphisms in the Murine Double Minute 2 (MDM2) gene, SNP285 G > C and SNP309 T > G, for the development of cervical lesions in a Southeastern Brazilian population (293 cases and 184 controls). MDM2 genotyping was performed by PCR-RFLP (Polymerase Chain Reaction-Restriction Fragment Length Polymorphism) and/or DNA sequencing. MDM2 SNP309 has potential as a biomarker of cervical neoplasia in non-smokers, patients with family history of cancer, or those who had late sexual debut (>16 years). Besides, this polymorphism may help identify women at risk of developing severe cervical lesion at a young age (<30 years).

Interaction between TP63 and MDM2 genes and the risk of recurrent pregnancy loss.

OBJECTIVE: Recent studies have investigated the role of the p53 gene family in reproductive processes. Each member of the gene family acts through different mechanisms: p53 is involved in genomic stability and regulation of blastocyst implantation; p63 acts as a regulator of the quality and maturation of oocytes; and p73 controls the meiotic spindle. Polymorphisms in the genes of the p53 family have been associated with female infertility. One polymorphism in MDM2, the main regulator of the p53 family, has also been associated with this condition. Although polymorphisms in the TP53 gene have been related to recurrent pregnancy loss (RPL), there have been no studies associating polymorphisms in p63 and p73 with RPL. Therefore, the aim of this study was to evaluate the role of polymorphisms in the TP63 (rs17506395), TP73 (rs2273953, rs1801173), and MDM2 (SNP309, rs2279744) genes as risk factors for RPL. STUDY DESIGN: A case-control study was conducted in 153 women with RPL and 143 fertile women with at least two living children and no history of pregnancy loss. Molecular analysis was performed by TaqMan Allelic Discrimination assay. The statistical analysis was performed using SPSS software version 20.0 and the chi-square test, Student's t-test, Mann-Whitney test and logistic regression to compare the evaluated characteristics between both groups and RPL outcome. RESULTS: The allelic and genotypic frequencies did not differ between the groups when analyzed separately, however, the interaction between the TP63 TT and MDM2 TT genotypes was shown to increase the risk of RPL (OR=2.19, CI 95%: 1.28-3.75, p=0.004), even when adjusted for alcohol consumption, smoking, number of pregnancies and ethnicity (OR=1.97, CI 95%: 1.27-3.58, p=0.025). CONCLUSIONS: Our results suggest that genes from the p53 family proteins, evaluated here, have an influence on the risk of RPL.