DNA-PLOIDY PATTERN AND TUMOR-SUPPRESSOR GENE P53 EXPRESSION IN GALLBLADDER CARCINOMA

The relationship between p53 gene expression and DNA content in advanc ed gallbladder carcinoma was studied. Fifty-three cases of advanced ga llbladder carcinoma (45 primary tumors and 8 metastases) were analyzed , p53 protein expression was determined by immunohistochemistry. DNA c ontent was measured by cytophotometric techniques, Study subjects incl uded 45 (85%) female and 8 male patients, with an overall mean age of 58.6 years, Positive staining for p53 protein was observed in 27 (51%) cases, In subserosal tumors, the expression was significantly less th an that in tumors that reached the serosa (P = 0.01), Twenty-nine (55% ) cases were diploid and 24 were aneuploid, Sixty-seven % of primary t umors were diploid, whereas 87% of metastases showed an aneuploid DNA content, Both diploid and aneuploid tumors were positive for the p53 p rotein in the same proportion, and p53 was also expressed equally in b oth primary and secondary tumors, In advanced gallbladder carcinoma, t he expression of the p53 gene was earlier than the accumulation of abn ormal quantities of chromosomal DNA in the tumor cells. The determinat ion of these events as markers in preneoplastic lesions is warranted i n gallbladder carcinogenesis.