Sulfated proteoglycans in the extracellular matrix of human breast tissues with infiltrating carcinoma

The size, content and distribution of sulfated proteoglycans, constituents of the extracellular matrix, were investigated in non-neoplastic human breast tissues and in tissues with infiltrating carcinoma. Sulfated proteoglycans were identified as cupro-linic-blue-positive elements on electron microscopy preparations by the method of the critical electrolyte concentration. Morphometric data indicated that the numerical density of PG per surface area (Na) in normal tissues was about 2 to 7 times higher respectively in dense or loose connective zone then that found in the corresponding zones of malignant tissues. By referring to the unit volume of tissue, the overall PG content (Nv) was found to be increased about 5 fold in nonneoplastic tissues. However, in tissues with carcinoma the average length of sulfated proteoglycans was about twice as long in dense and loose connective layers than in the corresponding connective zones of non-neoplastic breast tissues. Our findings provide evidence of profound structural alterations of non-collagenous constituents in the extracellular matrix of human mammary tissues concerned with infiltrating carcinoma.