Correlation of aromatase activity with histological differentiation of breast cancer--a morphometric analysis.

Differentiation is a term that indicates the degree to which a tumor resembles histologically the tissue or cell of origin. A system to quantitate the proportion of breast cancer cells participating in glandular differentiation or remaining within ducts was employed. The degree of tumor differentiation of 58 primary breast cancers was correlated with estrogen (ER) and progesterone receptors (PR) and tumor aromatase activity. There was a significant association between tumor differentiation (greater than or equal to 2% cancer cells exhibiting glandular differentiation) and the presence of ER or PR in tumors. Conversely, there was no correlation between tumor differentiation and measurable tumor aromatase activity.