Study of AP endonuclease (APEX1/REF1), a DNA repair enzyme, in gallbladder carcinoma.

ABSTRACT

AIM: This study investigated the levels of Apurinic/Apyrimidinic Endonuclease (APEX1) in gallbladder carcinoma (CaGB) tissue and co-related these levels with various clinicopathological parameters. PATIENTS AND METHODS: Twenty cases of CaGB and cholelithiasis were included in the study. Western blot analysis of APEX1 protein was performed using actin as the reference point. Densitometric analysis and the integrated density value (IDV) of APEX1 protein samples were determined. The ratio of IDV of APEX1/actin was determined. RESULTS: The mean IDV ratio of APEX1 in CaGB was 0.63±0.33 and 0.45±0.19 in cholelithiasis. The mean IDV ratio of a variant of APEX1 (ΔAPEX1) in CaGB was 0.50±0.09, whereas it was 0.40±0.16 in cholelithiasis. Calculating the mean IDV ratio of total APEX (APEX1+ΔAPEX1) in CaGB was 1.13±0.31 whereas in cholelithiasis, 0.85±0.23. The differences were statistically significant (p<0.05). CONCLUSION: A significant correlation was found between the relative expressions of APEX1 in cancer as compared to that in cholelithiasis patients. There was significant association between APEX1 expression and perineural invasion. A variant of APEX1 correlated with tumor infiltration. Hence APEX1 may be of use as a prognostic marker in patients with CaGB.