Luigi Frigerio

( In Coll. con A.Mariani, M.Castagnaro, A.Ferrari )
Summary: The p53 gene is located on the small arm of the cromosome 17 and mutations or hyperexpression are found in a high percentage of ovarian cancer cases ( 44-92%). We studied DNA extracted from blood leukocytes of 38 ovarian cancer patients tumor tissues were also available for analysis in 20 of these cases. Specimens were examined using Single Strand Conformation Polymorphism (SSCP) analysis and direct genomic sequencing of the p53 gene. Exons from 2 to 11 were studied in blood and tumoral tissues. Single Strand Conformation Polymorphism analysis and direct genomic sequencing showing that 7 patients (18.4%) had germline alteration of the p53 gene but only 2 of them (5.2%) led to and aminoacid change. The other 5 patients had only a silent mutation which those not change the aminoacid (2 patients) or had intronic mutations (4 patients) whose interpretation is uncertain. Somatic mutations of the p53 gene were found in 9 of the 20 tumoral tissues (45%). One tumor contained 2 mutatins in the p53 gene (no. 9). Our study, though preliminary and based on a small group of patients suggests that classic p53 mutations in sporadic ovarian cancer cases are common, but they are not generally found in the germinal line.