title: The expression of progesterone receptors coincides with an arrest of DNA synthesis in human breast cancer.
abstract: Two main models to account for the heterogeneous expression of estrogen receptors (ER) and progesterone receptors (PR) in human breast cancer have been proposed: the clonal model and the stem cell model. The authors previously provided evidence supporting the stem cell model since it was found that most of the proliferating cells in ER-positive (ER+) human breast cancer lack ER and that the ER-negative (ER-) and ER+ subpopulations are interrelated. The authors have analyzed in eighteen ER+/PR+ primary breast tumors the simultaneous expression of ER or PR (by immunohistochemistry) and DNA synthesis (by autoradiography) after 30 minutes of 3H-thymidine incorporation. The authors demonstrated that: (1) the average numbers of ER+ and PR+ cells were similar (36.8 +/- 10.7% and 39.3 +/- 17.6%, respectively); (2) The thymidine-labeling indexes of the ER+, ER-, PR+, and PR- subpopulations were 0.53 +/- 0.69%, 0.74 +/- 0.49%, 0.21 +/- 0.21 and 0.94 +/- 0.54%, respectively; and (3) 75.2% of the DNA-synthesizing cells were ER-, and 88.8% of them were PR-. The authors conclude that the cellular subpopulations expressing ER and PR were not identical, and the expression of PR was associated with a lower rate of cellular proliferation than was ER expression.
authors.affiliation: Hospital Mariano R. Castex, Buenos Aires, Argentina.
authors.forename: C
authors.initials: C
authors.lastname: Ballare
authors.forename: A I
authors.initials: AI
authors.lastname: Bravo
authors.forename: I
authors.initials: I
authors.lastname: Sorin
authors.forename: N
authors.initials: N
authors.lastname: Guman
authors.forename: J A
authors.initials: JA
authors.lastname: Schiaffi
authors.forename: R
authors.initials: R
authors.lastname: Yomha
authors.forename: A
authors.initials: A
authors.lastname: Bagnati
authors.forename: B
authors.initials: B
authors.lastname: Lema
authors.forename: J
authors.initials: J
authors.lastname: Mordoh
mesh_terms: D001943:Breast Neoplasms / Q000737:chemistry* / Q000235:genetics; D002277:Carcinoma / Q000737:chemistry / Q000235:genetics; D004261:DNA Replication / Q000502:physiology; D004273:DNA, Neoplasm / Q000032:analysis*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis*; D015203:Reproducibility of Results
chemical_list: D004273:DNA, Neoplasm; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone