Identification of a novel gene with increasing rate of suppression in highgrade prostate cancers

Prostate cancer is the second leading cause of cancer-related deaths in the United States. However, the underlying molecular events for prostate cance r development are not clear. In this study, we applied the recently develop ed technology known as differential subtraction chain (DSC) to identify a n ovel gene whose expression is inactivated in high grade prostate cancer. Th is gene, designated as SAPC, is expressed in normal prostate acinar cells. Its expression is dramatically down-regulated in high grade prostate cancer s (4/4) but is unaltered in low grade prostate cancers. It encodes a 7.7-kd protein. Its sequence shares some homology with the cysteine-rich domain o f 2-5A-dependent RNase L,which is a critical component of the interferon-in duced apoptosis cascade. The selective inactivation in the more aggressive prostate cancers holds promise for SAPC as a potential prognostic marker fo r high grade prostate cancer.