Desmoplasia in benign and malignant breast disease is characterized by alterations in level of mRNAs coding for types I and III procollagen.

Desmoplasia, the formation of excessive connective tissue surrounding some neoplasms, is a well documented, but incompletely understood phenomenon. To characterize the fibrotic response in benign breast conditions and malignancy, we examined the steady state levels of mRNA coding for types I and III procollagen in mild fibrocystic changes, in fibroadenoma, and in infiltrating ductal carcinoma. The results indicate that in mild fibrocystic change there is a relative increase in type III procollagen mRNA. In contrast, fibroadenoma and carcinoma are characterized by increased levels of type I procollagen mRNA.