Serum levels of carboxyterminal propeptide of type I procollagen in cancer patients with osteoblastic and osteolytic bone metastases.

Serial monitoring of serum and urinary markers of bone regeneration may provide an indirect assessment of the activity of bone metastases. We measured serum levels of carboxyterminal propeptide of type I procollagen (PICP), a new marker of bone formation, in 236 control subjects, stratified according to age and sex, and in 122 cancer patients: 80 with breast cancer (BC) (42 with osteolytic bone metastases) and 42 with prostate cancer (PC) (31 with osteoblastic bone metastases). An inverse correlation between age and serum PICP levels was found in healthy men (r = -0.30), but not in women, PICP levels were significantly higher in patients with osteoblastic metastases compared to age-matched control subjects and patients with advanced disease not involving the skeleton. The sensitivity of PICP was 64% for detecting osteoblastic metastases, and 12% for detecting osteolytic metastases. Serum PICP determination may have a diagnostic role for osteoblastic activity.