Although immunohistochemical analysis showed that the expression of haptoglobin in bone metastasis of prostate cancer was significantly higher than that in prostate cancer tissues, analysis of its expression in three cell lines (DU145, LNCaP and PC3) derived from different metastasis of prostate cancer indicated that PC3, which is derived from bone metastasis, had the lowest expression. The gene discussed is HP; the disease is prostate carcinoma.