The correlation of cytologic grade and steroid receptor content in effusions of metastatic breast carcinoma.

The synthesis of estrogen receptor (ER) and progesterone receptor (PR) proteins by mammary carcinoma cells is a manifestation of biochemical differentiation. This study was an attempt to determine whether this acquisition of functional differentiation correlates with cytologic differentiation. Malignant effusions from 30 patients with mammary carcinoma were studied. ER and PR were measured by sucrose density gradient analysis. Membrane filters of the effusions were prepared, and a cytologic grade was assigned based primarily on nuclear size and nucleolar prominence. Ten cases were classified as well differentiated, 15 as moderately differentiated and 5 as poorly differentiated. Four of the ten well-differentiated neoplasms contained greater than 7 fm/mg protein ER and PR. Six of the 15 moderately differentiated neoplasms contained significant levels of ER and PR. None of the five poorly differentiated neoplasms contained significant receptor. This study strongly suggests that there is a correlation between the cytologic grade and steroid receptor content in metastatic mammary carcinoma. In a prospective analysis of thin needle aspirations of breast cancers now underway, the nature of this relationship is being further defined.