The positive expression sites were on epithelial cells, while the mesenchyme was negative for CD59 expression.The expression intensity of CD59 was found progressively lower going from the bone metastatic tumor group to the prostate cancer with bone metastasis, prostate cancer without metastasis and prostate hyperplasia groups Therefore, we speculate that the increased expression of CD59 may prevent prostate cancer cells from being attacked by the immune system and facilitate their colonization in bone/marrow tissues, thereby leading to bone metastasis. This evidence concerns the gene CD59 and benign prostatic hyperplasia.