Bax upregulation may provide a rationale for the low incidence of esophageal adenocarcinoma in a Greek cohort of patients with Barrett's esophagus

BACKGROUND/AIMS: Previously rare, esophageal adenocarcinoma (EA) is now the most common esophageal malignancy in Western countries whose incidence is increasing faster than any other cancer. However, mortality from esophageal cancer in Greece is among the lowest in the world and no clear-cut answer has emerged as to why the incidence of EA is so low in this country. Thus, the aim of the study was to provide an explanation for the low incidence of EA in Greece through molecular-based ethnic differentiations. METHODOLOGY: Out of 270 patients who underwent upper gastrointestinal endoscopic and histologic evaluation due to GERD symptoms, 31 patients (23 males, 8 females, mean age 47.10 +/- 11.88 years) with BE (typical salmon-pink lesions) and 21 GERD controls (12 males, 9 females, mean age 46.57 +/- 17.71 years) were ultimately included in the study. Esophageal mucosa biopsy specimens were evaluated immunohistochemically for Ki-67, Bax and Bcl-2 expressions. RESULTS: Increased expression of Ki-67 was observed in BE patients compared with GERD controls (p = 0.01); increased expression of Bax was noticed in the total BE patients compared with GERD controls (p < 0.001); Bcl-2 expression did not differ between the two groups. CONCLUSIONS: Our findings indicate a possible existence of a balance between cell proliferation (indicated by Ki-67 increased expression) and apoptosis (indicated by Bax protein overexpression), thereby providing an equilibrium between cell apoptosis and cell proliferation, and this may partly explain the low EA incidence in Greece.