Expression of Bcl-2 and amplification of c-myc are frequent in basaloid squamous cell carcinomas of the esophagus.

Basaloid squamous cell carcinoma (BSCC) of the esophagus is a rare, poorly differentiated variant of typical esophageal squamous cell carcinoma (SCC) characterized by high proliferative activity and frequent spontaneous apoptoses. In the present study, we investigated the expression of the apoptosis-suppressing protein Bcl-2 in 23 BSCC of the esophagus and 23 stage-matched typical esophageal SCC by means of immunohistochemistry. In addition, amplification of the apoptosis- and proliferation-inducing gene c-myc was determined by means of differential polymerase chain reaction. Bcl-2 expression was found significantly more often in BSCC than in SCC (86.9% vs. 17.4%, P < 0.0001). Amplification of c-myc was nearly twice as common in BSCC as in SCC (47.8% vs. 26.1%, not significant). Bcl-2 protein expression together with c-myc amplification was detected in 43.5% of the BSCC but in none of the typical SCC (P < 0.0001). Taken together, our findings indicate that the molecular pathogenesis of esophageal BSCC differs from that of typical SCC and frequently involves coactivation of c-myc and Bcl-2.