[Property of scirrhous carcinoma of the stomach defined by collagen metabolism].

Scirrhous carcinoma of the stomach is characterized by the extensive deposition of collagen in the desmoplastic stroma. In the present study, we examined which cell types are responsible for the synthesis of collagen in tissue of scirrhous carcinoma. Furthermore, a RIA for carboxyterminal peptide of human type I procollagen (type I C-peptide) was developed and its clinical implication for serodiagnosis of scirrhous carcinoma of the stomach was evaluated. 1) The immunohistochemical localization of type I procollagen was investigated employing an antibody to procollagen. Strong staining was observed in the cytoplasma of scirrhous carcinoma cells. Furthermore northern blot technique using c-DNA probe of type I procollagen was performed. Tumor cells established from scirrhous carcinoma (KATO III) were expressing mRNA-procollagen type I as revealed by this technique. Thus in scirrhous carcinoma of the stomach, at least some portion of the increased collagen content is due to production by the tumor cells. 2) In scirrhous carcinoma of the stomach, serum type I C-peptide level appeared to increase, while in non-scirrhous carcinoma, serum type I C-peptide level stayed within normal range. Serum type I C-peptide levels corresponded to clinical course who underwent either operation or chemotherapy. Collectively, the measurement of serum type I C-peptide concentrations will provide a new means for diagnosis and monitoring the scirrhous carcinoma of the stomach.