Aminoterminal propeptide of the alpha 1-homotrimer variant of human type Iprocollagen (hotPINP) in malignant pleural effusion

The aminoterminal propeptide (hotPINP) of type I homotrimer, a putative mal ignancy-associated type I collagen variant, was purified for the first time and a method was established for its detection in pleural fluid. Samples o f 58 patients, with malignant or benign disease, were studied with specific immunoassays for the two propeptides of type-I procollagen (PICP and PINP) and with HPLC-DEAE chromatography to separate the two PINP variants. HotPI NP was present in 64 % of both benign and malignant pleural effusion fluids , with the exception of malignant mesotheliomas, none of which showed the p resence of hotPINP. Also the PICP to PINP ratios were lower than normal in both benign and malignant samples (altogether in 69 % of samples), although this deviation was greater in malignancy. These two phenomena were indepen dent of each other. As synthesis of the a1-homotrimer-variant of type-I col lagen seems to be relatively common during the formation of pleural effusio n, it may be generally related to a fibroproliferative reaction in the pleu ral wall.