Amplification and overexpression of EXP1 and EXP2/Cyclin D1 genes in human esophageal carcinomas.

We previously identified two genes, EXP1 and EXP2/Cyclin D1, about 120 kb apart from HST1 and INT2 on human chromosome 11q13. Here we report the frequent amplification and overexpression of these genes in surgically resected esophageal carcinomas. Amplification was observed in 8 out of 22 cases. In the tumors with the amplification, these genes were overexpressed, while in the tumors without the amplification, expression levels of these genes were almost the same as those with normal mucosa. These results suggest that EXP1 and/or EXP2/Cyclin D1 may play an important role in the progression of human esophageal carcinomas.