[Study on stromal component of mastopathy--content and type of collagen]

Mastopathy is one of most common diseases involving adult female. Hormonal disturbance is implicated to play one role promoting the disease; however, the role of stromal component, i. e., collagen has not been examined to discuss its pathogenesis. The present study is to investigate the difference of content and type of collagen between mastopathy and normal mammary tissue. In addition, other mammary tumors were also studied. Materials were consisted of 8 cases of normal control, 23 mastopathy, 11 fibroadenoma, and 26 carcinoma. The content of collagen was analysed using a Woessner's method. The typing of collagen was determined by amino acid analysis, densitometry, and electron microscopy. The results were as follows; 1. Normal. The content was 59.8 +/- 4.0% (mean +/- SE). The collagen type was classified as type I. 2. Mastopathy. 58.9 +/- 4.0 The collagen was composed of both type I and type III. 3. Fibroadenoma. 56.3 +/- 3.5, type I 4. Carcinoma. Except for the scirrhous carcinoma, its content was 50.7 +/- 2.2. Type I 5. The amino acid composition of the mastopathy except for the fibrosing type demonstrated high levels of hydroxyproline and glutamic acid and low levels of hydroxylysine, histidine, and arginine. That of the carcinoma showed only increased level of histidine. 6. The rate of lysyl hydroxylation of collagen in the normal control was 39.2% and the carcinoma 26.1%. With regard to the content of collagen, there was no significant difference between the cases of mastopathy and normal control. However, in the mastopathy, an aberrant type of collagen, i.e., type III was detected. The amino acid composition and rate of lysyl hydroxylation of the mastopathy differed from those of the carcinoma. This indicates that there is a maturation disturbance of collagen in the development of mastopathy. In conclusion, it is considered that analysing these two factors may be one diagnostic aid to predict the malignant transformation of mastopathy.