Factors associated with prognosis in human breast cancer. IV. Progesterone receptors and clinical factors.

We have found no correlation between progesterone receptor PgR content in human breast tumors and clinical factors associated with the presence of estrogen receptor (ER, age, menopausal status, parity, age at first childbirth, menarche), in spite of the positive correlation between both receptors. Moreover, the association between clinical factors and the percentage of ER(-) PgR(-) tumors were identical to those of ER(-) tumors, but the association between clinical factors and the percentage of ER(+) PgR(-) tumors were inverse to those of ER(-) tumors. That implies that clinical factors associated with the presence of estrogen receptor can not distinguish ER(+) PgR(+) and ER(+) PgR(-) tumors. The stage of the disease is the most important clinical feature in breast cancer patients. In our series the pattern of hormone-receptor was different between Stages I/II and Stage III patients, while the percentage of PgR(+) tumors was constant, a decrease in ER(+) tumors occurred in Stage III patients. In addition similar percentages of ER(+) PgR(+) were found in both groups, but an increase in ER(-) PgR(-) tumors and a decrease in ER(+) PgR(-) tumors occurred in the Stage III patients. Altogether these results suggest that primary loss of progesterone receptors and primary loss of estrogen receptors could be related to different pathogenic mechanisms.