We also found that carriage of TPCN2 rs3750965:GG/GA is associated with an increased risk of cancer recurrence susceptibility in patients with prostate cancer and rectal cancer (GG OR: 1.07, 95% CI: 0.94–1.22, P = 0.018, GA OR: 1.4, 95% CI: 1.05–1.85, P value = 0.0199*, respectively, vs. A/A), indicating the possibility of utilising this genetic variant to predict cancer recurrence in patients with prostate and rectal cancer. The gene discussed is TPCN2; the disease is Familial prostate cancer.