Although prostate cancer is the most common non-cutaneous malignancy diagnosed in men in the United States1,2, little is known about inherited factors that influence its genetic predisposition3,4,5. Here we report that germline mutations in the gene encoding 2′-5′-oligoadenylate(2-5A)–dependent RNase L (RNASEL)6,7,8 segregate in prostate cancer families that show linkage to the HPC1 (hereditary prostate cancer 1) region at 1q24–25 (ref. 9). We identified RNASEL by a positional cloning/candidate gene method, and show that a nonsense mutation and a mutation in an initiation codon of RNASEL segregate independently in two HPC1-linked families. Inactive RNASEL alleles are present at a low frequency in the general population. RNASEL regulates cell proliferation and apoptosis through the interferon-regulated 2-5A pathway and has been suggested to be a candidate tumor suppressor gene10,11,12. We found that microdissected tumors with a germline mutation showed loss of heterozygosity and loss of RNase L protein, and that RNASEL activity was reduced in lymphoblasts from heterozyogous individuals compared with family members who were homozygous with respect to the wildtype allele. Thus, germline mutations in RNASEL may be of diagnostic value, and the 2-5A pathway might provide opportunities for developing therapies for those with prostate cancer.
We wish to thank the affected individuals and their family members who made this study possible. We thank D. Freije, H. Suzuki, E. Wilkens, A. Kibel, G. Bova, S. Gregory and T. Bonner for contributions to earlier phases of this work; F. S. Collins for input and comments; J. Qian for FISH analyses; M. Emmert-Buck for help in laser-capture microdissection; J. Hicks for immunohistochemistry; and J.R. Okicki for synthesizing the fluorescein-tagged 2-5A.This work was supported in part by grants from the PHS (SPORE), DOD, CaPCURE (W.I.) and the Fund for Research and Progress in Urology, the Johns Hopkins University, the Swedish Cancer Society and the SSF Genome Program (H.G.), the V Foundation for Cancer Research (J.S.), the Finnish Cultural Foundation, the Helsingin Sanomat Foundation, the Paulo Foundation, the Ella & Georg Ehrnrooth Foundation and the Maud Kuistila Foundation (N.N.), the NIH (R.J. and R.H.S.), and DOD (J.X.).