Study of morphology with assessment of expression of proliferation marker Ki67 antigen and P53 protein in lesions of gall bladder.

Objective: To study the spectrum and distribution of histopathological changes and evaluate immunohistochemistry markers p53 protein and Ki67 antigen in various lesions of gall bladder.

Materials And Methods: A total of 804 consecutive gall bladder specimens were evaluated. Forty cases were selected for immunohistochemical analysis to evaluate expression of p53 and ki67 proliferation index, including 20 carcinoma gall bladder cases and 20 cases of inflammatory pathology associated with metaplasia, atypia, hyperplasia, dysplasia, and adenoma. p53 immunostaining was categorized as wild type and mutant type. ki67 of >20% was considered high expression.

Results: The majority of the gall bladder lesions were inflammatory in origin, most common being chronic cholecystitis. In the group of 20 gall bladder carcinoma cases, 65% were p53 mutant and the remaining 35% cases had a p53 wild-type immunophenotype. 55% cases showed high expression for ki67 labeling. However, significant correlation ( P < 0.05) was seen with lympho-vascular invasion. Among non-malignant lesions, normal/wild-type p53 expression was seen with increasing intensity and positivity in lesions with atypia and intra-epithelial neoplasms. Ki67 index also showed the same trend in all cases.

Conclusions: p53 and ki-67 expression increases in inflammation, and further increment occurs in premalignant and malignant lesions of the gall bladder epithelium and can be used as a marker of aggression of histopathological lesions. The results emphasize the potential of Ki-67 and p53 as biomarkers of carcinogenesis in gall bladder carcinoma.