Immunohistochemical markers in the study of gallbladder premalignant lesions and cancer.

AIM: The aim of the study was to perform a comparative analysis of proliferative and apoptotic activity as well as of microvascular density (MVD) in metaplasia, dysplasia and gallbladder carcinoma.

MATERIAL AND METHOD: There were investigated 10 cases of chronic cholecystitis associating premalignant lesions and 5 cases of gallbladder carcinoma developed on a chronic cholecystitis background. The immunohistochemical (IHC) staining was made using Ki-67, p53 and CD34 antibodies, and the streptavidin-biotin method. The semiquantitative analysis focused on the intensity of the IHC reaction for Ki-67 and p53 (on a scale from 0 to 4), the Ki-67 index and the percentage of p53 positive cell nuclei. The MVD was established on 5 representative fields as mean of the number of CD34 positive vessels.

RESULTS: Ki-67 was positive in all 10 chronic cholecystitis cases (100%) and in all 5 carcinoma cases (100%), which is explainable by the selection manner of chronic cholecystitis associating premalignant lesions and by the invasive pattern of the carcinomas. Ki-67 index rose from 10% in simple dysplastic lesions associated with chronic cholecystitis to 20% in severe dysplastic lesions associated with chronic cholecystitis up until 90% in carcinoma. In all chronic cholecystitis, p53 was negative for normal gallbladder epithelium, in metaplastic territories and in those with mild dysplasia. In the dysplastic areas present in chronic cholecystitis, the positive reaction of p53 rose from 20% (in moderate dysplasia) to 80% (in severe dysplasia). All carcinoma cases were p53 positive (100%), its expression varying from 30% in papillary areas and 30-50% in undifferentiated adenocarcinoma to 80-100% in well differentiated type. In chronic cholecystitis MVD was of 5-9 vessels / field in areas adjacent to pyloric metaplasia and 10-20 vessels / field in severe dysplastic areas. Gallbladder carcinoma cases presented a MVD of 15-30 vessels / field.

CONCLUSIONS: The investigation of Ki-67, p53 and MVD brings important data regarding the carcinogenesis process in the gallbladder, initiated on the background of a chronic cholecystitis. The dynamics in the values for Ki-67, p53 and MDV followed from premalignant lesions to carcinoma sustains the hypothesis of the metaplasia-dysplasia-carcinoma sequence.