RNASEL and Familial prostate cancer: However, beyond the established antiviral effect via nucleolytic function, little is known about the antitumor function of RNase L. Four germline mutations in HPC1/RNASEL have been identified in hereditary prostate cancer cases: M1I (start codon substitution), E265X (stop codon at 265), 471ΔAAAG (deletion causing a frameshift and stop codon) and R462Q (missense mutation at 462) [8,9,10,11].