The importance of somatic TP53 mutations and germline TP53 codon 72 genotype in the survival of women with epithelial ovarian cancer is controversial. Recent data suggest that a promoter polymorphism in the MDM2 gene may influence age of cancer onset in a gender-specific fashion. We sought to determine the relationship between somatic TP53 mutations, germline genotypes at TP53 codon 72 and MDM2 SNP309, and overall survival and response to chemotherapy in a large series of patients with ovarian and peritoneal carcinomas. Of the 188 cancers, 103 (54.8%) had a TP53 mutation, of which 71% were missense mutations and 29% were null mutations. TP53 mutation status and mutation type (null vs. missense) did not influence response to therapy or overall survival. Women with the codon 72 Pro/Pro had a decreased overall survival (median, 29 months) compared with women with one or two arginine alleles (median, 49 months; P=0.04). Somatic mutation or deletion was equally common for either codon 72 allele. Age of diagnosis was not influenced by codon 72 but showed a trend for younger age in women with somatic TP53 mutations and the MDM2 G/G genotype.
Objectives-To define patterns of aberrant DNA methylation, p53 mutation and Her-2/neu overexpression in tissues from benign (N=29), malignant (N=100), and border line malignant ovaries (N=10), as compared to normal (N=68) ovarian tissues. Further, to explore the relationship between the presence of genetic and epigenetic abnormalities in ovarian cancers, and assess the association between epigenetic changes and clinical stage of malignancy at presentation and response to therapy.Methods-The methylation status of 23 genes that were previously reported associated with various epithelial malignancies was assessed in normal and abnormal ovarian tissues by methylation specific PCR. The presence of p53 mutation (N=82 cases) and Her-2/neu overexpression (N=51 cases) were assessed by DNA sequencing and immunohistochemistry, respectively. Results-Methylation of four genes (MINT31, HIC1, RASSF1, and CABIN1) was significantly associated with ovarian cancer but not other ovarian pathology. Her-2/neu overexpression was associated with aberrant methylation of three genes (MINT31, RASSF1, and CDH13), although aberrant methylation was not associated with p53 mutations. Methylation of RASSF1 and HIC1 was more frequent in early compared to late stage ovarian cancer, while methylation of CABIN1 and RASSF1 was associated with response to chemotherapy.Conclusion-DNA methylation of tumor suppressor genes is a frequent event in ovarian cancer, and in some cases is associated with Her-2/neu overexpression. Methylation of CABIN1 and RASSF1 may have the utility to predict response to therapy.
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