2-mismatch in HLA-A and HLA-B groups was a risk factor of prostate cancer after KT [1.19(1.01~1.40)]; 2-mismatch and 1-mismatch were both risk factors of prostate cancer after KT in the HLA-DR group [1.32(1.13~1.54)], [1.20(1.03~1.39)]. The gene discussed is HLA-A; the disease is prostate carcinoma.