Accordingly, the levels of serum tartrate-resistant acid phosphatase 5b (TRACP5b), carboxy-terminal pyridinoline cross-linked telopeptide of type I collagen (ICTP), procollagen type I amino-terminal propeptide (PINP), and bone alkaline phosphates (BAP) have been used to estimate bone destruction in patients with bone metastatic cancers, such as prostate cancer [15–17]. The gene discussed is ACP5; the disease is prostate cancer.