Relationship between progesterone receptor and productive fibrosis as an index of tumor differentiation in breast cancer.

We studied the relationship between steroid receptors (SR) and various stromal parameters in 100 breast cancers. Each specimen was submitted to SR determination by the dextran-coated charcoal assay and to histologic examination. No relationship was found between the presence of SR and necrosis or fibroblastic cell content. There was an inverse correlation between SR positivity and the extent of lymphocyte infiltration (p less than 0.05). ER + PR + status was strongly correlated with marked productive fibrosis (PF) (p less than 0.005). When SR were separately assayed, only the presence of PR was correlated with PF (p less than 0.005); similar results were obtained for PR levels (p less than 0.01). PF was also associated with a higher nuclear grade (p less than 0.001). In conclusion, in this study a strong correlation between PR positivity or concentration and extent of PF was demonstrated in breast cancer. Since PR synthesis is an expression of an intact regulatory pathway, our data suggest that stromal production in breast cancer is related to the degree of differentiation of malignant epithelial cells.