One hundred and sixty-three breast carcinomas occurring in women aged between 26 and 44 years were examined for pathological features, oestrogen and progesterone receptor status, proliferation as determined by Ki-67 labelling and the presence of c-erbB-2 and p53 protein, and were compared with a control group of carcinomas from women in the 50-67 years age group.
We conclude that sequence aberrations in the DNA binding domain of the ER are not a common cause of absent PR expression in ER (+)/PR (-) breast carcinomas.
The small numbers of cases in some categories and the corresponding wide CIs preclude definitive conclusions, but these data are at least suggestive that joint stratification of breast tumors on ER and PR status may be useful in partitioning breast cancer families into more homogeneous subsets.
Patients with BRCA1-associated breast cancer had twice as many progesterone-receptor-negative tumours (p<0.005) and development of contralateral breast cancer was four to five times as frequent as in the sporadic group (p<0.001).
The relative level of expression of some estrogen receptor variant mRNAs and possibly progesterone receptor variant mRNAs is altered during breast tumorigenesis and breast cancer progression.
If this smaller PR species exhibits similar differences in function as have been evidenced in vitro for PR A relative to PR B, it is possible that this PR species may be an important component in determination of progesterone response in breast cancer.
Thus, loss of PR expression in breast cancercannot be explained only by loss of chromosome 11; other genetic or non-genetic mechanisms should be advanced.
The expression of epidermal growth factor receptor (EGFR) mRNA and protein has been determined in a group of breast carcinomas and compared to oestrogen and progesterone receptor (ER, PgR) status, as well as pathological features.
However, few data about the mRNA expression of ER, PR, pS2, and PAI-1 in breast cancer are available, which is mostly due to the limitations of conventional techniques for mRNA analysis.
A correlation between ER-beta mRNA expression with ER and progesterone receptor (PR) protein levels as well as prognostic factors remains to be established in breast carcinoma.
Induction of progesterone receptor by E2 is suppressed by 1,25(OH)2D3, and the E2-mediated increase in breast cancer susceptibility gene (BRCA1) protein is reduced by 1,25(OH)2D3 treatment.
To clarify this hypothesis, the effects of hypoxia on the growth responses to hormonal agents and the expression levels of estrogen receptor (ER)-alpha and progesterone receptor (PgR) were investigated in two human breast cancer cell lines, ML-20 and KPL-1.
Estrogen receptor and progesterone receptor positive human breast cancer cell lines, T47D and MCF-7, were utilized for determining influence of hormonal and antihormonal agents on the level of expression of p53, state of phosphorylation of pRB, and rate of cell proliferation.