AGGRESSIVE BREAST-CANCER LEADS TO DISCREPANT SERUM LEVELS OF THE TYPE-I PROCOLLAGEN PROPEPTIDES PINP AND PICP

The propeptides PICP and PINP are derived from the synthesis of type I collagen, a major matrix protein of bone and soft tissues. The aim of this cross-sectional study was to investigate their value as indicato rs of the aggressivity of breast cancer. Serum PINP, PICP, and total a lkaline phosphatase were determined from 89 breast cancer patients. Fo rty had major bone and/or soft tissue metastases with an aggressive di sease course: the progressive disease (PD) group. Forty-nine had eithe r none or minor bone and/or soft tissue metastases with a stable clini cal course: the stable disease group (SD), The mean value of PINP in t he PD group was 7.2 times higher than that in the SD group (276 +/- 79 mu g/l versus 38 +/- 3 mu g/l, respectively; P = 0.005), whereas PICP mean value was only 1.7 times higher in the PD group (174 +/- 20 mu g /l versus 100 +/- 5 mu g/l; P = 0.001). The ratio of PICP to PINP was 1.02 +/- 0.07 in the PD group and 3.07 +/- 0.18 in the SD group (P < 0 .001), The correlation between PICP and PINP was linear in the SD grou p and nonlinear in the PD group. The results indicate that high serum PICP and PINP concentrations and a Low PICP:PINP ratio are associated with a highly aggressive nature of breast cancer. Determination of PIN P, in particular, may be valuable when evaluating the clinical status of a breast cancer patient.