Study of expression of p53 and Ki-67 in Benign, premalignant, and malignant lesions of the gallbladder

Background: Gallbladder cancer (GBC) has a distinctly higher incidence in certain demographic groups and areas. Chronic cholecystitis and epithelial changes such as metaplasia/dysplasia are associated with a higher incidence of gallbladder carcinoma. Progression from chronic cholecystitis to metaplasia/dysplasia to carcinoma is multifactorial. Ki-67 and p53 are involved at various stages of the cell cycle, and altered expressions of Ki-67 and p53 have been implicated in the carcinogenesis of various malignant tumors. Materials and Methods: Eighty gallbladder specimens were included in the study. Cases were grouped as chronic cholecystitis (Group 1), metaplasia-dysplasia (Group 2), and GBC (Group 3). P53 and Ki-67 immunoexpressions were determined and results were compared between groups. Results: The p53 expression score was highest in Group 3 (4.35 ± 1.72) and lowest in Group 1 (0.73 ± 0.98). The difference in the mean level of p53 expression was significantly (P = 0.0001) different among the groups. Ki-67 index was highest in Group 3 (47.85 ± 17.46) and lowest in Group 1 (6.50 ± 3.88). The mean Ki-67 index was significantly higher in Group 3 compared to Groups 1 and 2. P53 overexpression and Ki-67 expression were significantly associated with the presence of GBC (P = 0.0001). There was a positive correlation (r2 = 0.37, P = 0.001) between the expressions of p53 and Ki-67. Conclusion: P53 overexpression and Ki-67 index were significantly higher in the patients with GBC compared to those with chronic cholecystitis. This supports the theory of progression from chronic cholecystitis to metaplasia/dysplasia to carcinoma in the gallbladder. The expressions of p53 and Ki-67 in the metaplasia and dysplasia group were between the GBC and chronic cholecystitis groups.