Deletion at 13q21 is associated with aggressive prostate cancers

Previous cytogenetic and molecular genetic analyses suggest that the q21 band of chromosome 13 harbors a tumor suppressor gene(s) involved in prostatic carcinogenesis. The precise genetic location, however, has not been defined. In this study, we examined prostate cancer specimens and cell lines/xenograft for genetic deletions at 13q21, using the methods of tissue microdissection and duplex PCR. Deletions at 13q21 were detected in 13 of 147 (9%) prostate cancer samples. Deletion of the same region was also detected in the LNCaP cell line and the PC-82 xenograft of prostate cancer. The overlapping region of deletion in LNCaP and PC-82 spans 3.1 cM or 2.9 cR, which is equivalent to 1-3 Mb. The endothelin receptor B gene, a possible tumor suppressor gene at 13q21, was not located in the region of deletion. Among the 13 prostate neoplasms with deletion at 13q21, 5 were metastases, and 7 were poorly differentiated primary tumors. The only primary tumor that was not poorly differentiated but had deletion occurred in one of the youngest patients (49 years) at diagnosis. These results provide evidence that 13q21 may harbor an unidentified gene(s) whose inactivation occurs in some aggressive carcinomas of the prostate. In addition, this study provides a framework for the cloning and identification of the 13q21 gene(s).