Progesterone receptors A and B and estrogen receptor alpha expression in normal breast tissue and fibroadenomas.
Fibroadenomas are the most common benign breast tumors, occurring mainly in young women. Their responses to the hormonal environment are similar to those of normal breast tissue, which suggests that steroid receptors may play a role in tumor development. We evaluated the gene and protein expression of progesterone receptors A and B (PRA and PRB) and the protein expression of estrogen receptor alpha (ER-alpha) in fibroadenoma samples, comparing with adjacent normal breast tissue, from 11 premenopausal women. Progesterone and estradiol levels were determined. No alterations in the PRs gene and protein expression and the ER-alpha protein expression were observed between the follicular and luteal phases, in normal breast versus fibroadenomas. Protein levels of PRA and PRB were higher in fibroadenomas compared to normal breast tissue (P = 0.038 and P = 0.031), while the PRs mRNA levels were similar in both tissues (P = 0.721 and P = 0.139). There were no differences in ER-alpha protein expression between normal breast tissue and fibroadenomas (P = 0.508). The PRA:PRB ratio was similar in the tissues, and also showed a strong correlation in both (r = 0.964, P = 0.0001). Our data suggest a role of PRs in the growth and development of fibroadenomas, although without alterations of the PRA:PRB ratio in these tumors. The absence of alterations in ER-alpha protein levels could be a characteristic behavior of fibroadenomas, unlike breast cancer.
Laboratory of Endocrine and Tumoral Molecular Biology, Department of Physiology, Universidade Federal do Rio Grande do Sul, CEP 90 050-170, Porto Alegre, RS, Brazil.
Gisele
G
Branchini
Lolita
L
Schneider
Rodrigo
R
Cericatto
Edison
E
Capp
Ilma Simoni
IS
Brum
D000328:Adult; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism; D047628:Estrogen Receptor alpha / Q000235:genetics* / Q000378:metabolism; D005260:Female; D018226:Fibroadenoma / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D042361:Mammary Glands, Human / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000235:genetics* / Q000378:metabolism
D047628:Estrogen Receptor alpha; D011980:Receptors, Progesterone; C101118:progesterone receptor A; C097314:progesterone receptor B