BCAS2 is a novel gene isolated from breast cancer cell line by differential display technique. Previously we reported that BCAS2 gene is localized on chromosome 1p13.3-21 and is up-regulated by gene amplification in breast cancer cell lines MCF-7 and BT-20. In this study, we investigated the amplification of the BCAS2 gene in a series of 104 gynecological primary tumors by means of Southern blot analysis. The BCAS2 gene was amplified in two of 60 primary breast cancer tissues, whereas no amplification was detected in any of endometrial (0/26) and cervical (0/18) tumor tissues. Gene amplification was also not detected in a series of pancreatic (0/9) and gastric (0/6) cancer cell lines. An enhanced green fluorescent protein assay revealed that BCAS2 protein seems to be translocated into the nucleus. Although frequent deletions of the proximal region of chromosome 1p13.3-21 have been found in primary breast cancer, our results support first evidence of amplification within this region and indicate that BCAS2 gene codes for a nuclear protein.