DNA synthesis in estrogen receptor-positive human breast cancer takes place preferentially in estrogen receptor-negative cells.

The primary breast tumors of 27 patients were analyzed for the expression of estrogen receptors (ER) and DNA synthesis. Seventeen tumors were ER-positive, and the simultaneous expression of ER and DNA synthesis could be analyzed in 14 ER-positive tumors. DNA synthesis was measured through the thymidine labeling index (TLI). ER expression was detected by immunohistochemistry with monoclonal antibodies. In these tumors, 38.6% +/- 13.1% of the cells were ER-positive (average TLI = 0.60% +/- 0.70%), as opposed to the presence of 61.4% +/- 13.1% of ER-negative cells (average TLI = 0.65% +/- 0.53%). In 12 of 14 tumors, both ER-positive and ER-negative cells were found to be engaged in DNA synthesis, whereas in two tumors only ER-negative cells were synthesizing DNA. On the basis of the TLI and the proportion of ER-negative and ER-positive cells in the total population, it is suggested that the ER-positive and ER-negative compartments are interrelated in most tumors. In five tumors, the ER-negative compartment would be a precursor of the ER-positive segment, whereas in six tumors the ER-positive segment appears to be a precursor of the ER-negative one. In three tumors, no evidence of an interrelationship between both segments could be found. In the 14 tumors analyzed, it also was found that 69.1% +/- 21.3% of the DNA-synthesizing cells were ER-negative; this probably accounts for the temporary remissions observed after hormonal treatment in breast cancer.

Less efficacy with alternating regimen as adjuvant chemotherapy in stage II node-positive breast cancer: results at 8 years (Pronacam 85).

A randomized trial to compare adjuvant treatment with an alternating regimen with conventional chemotherapy was performed. A total of 589 node-positive patients were included and stratified according to number of positive nodes (N1-3 and N > 4) and menopausal status. Premenopausal N1-3 patients were randomized to cyclophosphamide, methotrexate and fluorouracil (CMF) or CMF/4'-epirubicin, cyclophosphamide (EC), post-menopausal N1-3 patients to fluorouracil, 4 epirubicin, cyclophosphamide (FEC) or CMF/EC and pre- and post-menopausal patients with N > or = 4 to fluorouracil, 4' epirubicin, cyclophosphamide, methotrexate, prednisone (FECMP) or CMF/EC. In premenopausal patients, CMF was superior to CMF/EC in terms of disease-free survival (DFS) (65% vs 45%, P = 0.0149) and survival (72.3% vs 50.2%, P = 0.0220) whereas, for N > or = 4 patients, differences between FECMP and CMF/EC did not achieve statistical significance (DFS 35% vs 26.2%; survival 50% vs 38.1%, P = NS). For post-menopausal patients, FEC was superior to CMF/EC in DFS (58.6% vs 36.8%, P = 0.0215) and survival (66.2% vs 46%, P = 0.0155). In post-menopausal patients with N > 4, differences favouring CMF/EC were significant in DFS (40.4% vs 22%, P = 0.0371) but not in survival (47.4% vs 32.2%, P = 0.1185). Alternating regimens did not offer better results in premenopausal and post-menopausal N1-3 patients. Results regarding post-menopausal N > 4 women require further confirmation.