p53, carcinoembryonic antigen and carbohydrate antigen 19.9 expression in gall bladder cancer, precursor epithelial lesions and xanthogranulomatous cholecystitis.

Background: Gallbladder cancer (GBC) is the commonest gastrointestinal cancer in women of north India. Precursor epithelial lesions in GBC are known; however, the role of xanthogranulomatous (XG) inflammation in the pathogenesis of GBC is unknown.
Aims: To analyze the role of precursor lesions in the pathogenesis of GBC we studied the immunohistochemical (IHC) expression of p53, carcino-embryonic antigen (CEA) and carbohydrate antigen 19.9 (CA-19.9) in GBC, chronic cholecystitis (CC), XG cholecystitis (XGC) and precursor lesions.
Materials and Methods: The study included 51 GBC, 68 CC, 42 XGC and 10 normal gallbladders. All cases were evaluated for presence of precursor lesions and IHC was performed.
Results: p53 immunoreactivity was found in 55% GBC, 32% of dysplasia with malignancy and in 14% of dysplasia with CC. Sixteen percent GBC had associated XG inflammation. Normal and metaplastic epithelium in CC and in XGC did not express p53. CEA expression was apical in normal and inflammatory GBs (CC, XGC), while cytoplasmic focal to diffuse positivity was seen in 82% GBC. CA-19.9 expression was seen in all cases of normal and inflammatory GBs; however, foci of antral metaplasia were negative. Seventy-five percent of GBC expressed CA-19.9; all negative cases were high-grade on histology.
Conclusions: Altered CEA expression is seen in GBC as compared to normal and inflammatory gallbladders. Loss of expression of CA19.9 in antral metaplasia and poorly differentiated GBC may indicate that it is a marker of biliary differentiation. p53 over-expression seen in GBC and in dysplasia associated with malignancy and with CC suggests that p53 mutation and dysplasia are early events in the evolution of GBC. Epithelial metaplasia and XG inflammation are often associated with GBC but do not appear to play a role in its pathogenesis through the p53 pathway.