CORRELATION OF P53 PROTEIN EXPRESSION WITH GENE MUTATION IN GALLBLADDER CARCINOMAS

The correlation of p53 protein expression and p53 mutation of 33 gall- bladder carcinomas was studied according to the depth of invasion and grade of cytological atypia. Overexpression of p53 protein was detecte d by immunostaining in seven (70.0%) of 10 intramucosal and in 16 (69. 6%) of 23 invasive carcinomas. p53 mutation was detected in five (71.4 %) of the seven intramucosal carcinomas with overexpression and in eig ht (50.0%) of the 16 invasive cancers with overexpression and in one ( 10%) of the 10 non-overexpressing carcinomas at exons 5-8 by nested po lymerase chain reaction-single-strand conformation polymorphism. The o verexpression of p53 protein was present in nine (56.3%) of 16 low-gra de carcinomas and in 14 (82.3%) of 17 high-grade carcinomas. in cases of overexpression, p53 mutation was detectable in four (44.4%) of nine low-grade and in nine (64.3%) of 14 high-grade carcinomas. In total, p53 mutation was verified in 56.5% (13/23) of cases involving protein overexpression and in 10% (1/10) of cases of non-overexpression. The s ensitivity of p53 mutation was 56.5% (13/23), the specificity was 90.0 % (9/10) and the validity was 1.47. In conclusion, our study indicates that p53 protein overexpression correlates well with gene mutation an d that p53 alteration may be related to increasing grade of cytologic atypia of carcinomas.