Gallbladder carcinoma: the role of p53 protein overexpression and Ki-67 antigen expression as prognostic markers.

BACKGROUND

The overexpression of p53 protein and the expression of Ki-67 antigen may affect the survival of patients with gallbladder carcinoma. This association has been tested in a series of 41 patients with relatively early carcinoma of the gallbladder.

METHODS

Forty-one surgical specimens from patients with a postoperative histological diagnosis of gallbladder carcinoma were studied. All patients were operated by simple cholecystectomy only because the tumours were not advanced and/or their general condition was poor. Patients submitted to radical operations were excluded. p53 expression was calculated from nuclear staining according to the intensity and extent of positive cells, as graded on a scale from 1 to 3; a combined score of >3 was considered as overexpression. Ki-67 expression was calculated by the MIB-I index: the percentage of positively stained tumour cell nuclei out of the total tumour cells counted (n = 1000); >20% of stained cells was considered positive.

RESULTS

Twenty-nine gallbladder carcinomas (71%) overexpressed p53 protein in the cell nuclei. No significant differences were found in relation to cell differentiation on the level of tumour infiltration through the gallbladder wall. Five-year survival of patients with gallbladder carcinoma overexpressing p53 was 17.2%, while survival of patients without p53 overexpression was 30% (not significant). Twenty-four cases (58.5%) were considered positive for the MIB-I index. There were no differences between the grade of cell differentiation and wall infiltration. Five-year survival of the patients with a MIB-I positive index was 9.2% as opposed to 27.7% for those with a negative index (not significant).

CONCLUSIONS

p53 protein nuclear overexpression and Ki-67 protein expression in gallbladder carcinoma were not related to histological differentiation, level of gallbladder wall invasion or patient survival.