Estrogen receptor-α, bcl-2 and c-myc gene expression in fibroadenomas and adjacent normal breast: Association with nodule size, hormonal and reproductive features

• Published in: Steroids Vol. 70; no. 3; pp. 153 - 160
• Main Authors: Cericatto, R., Pozzobon, A., Morsch, D.M., Menke, C.H., Brum, I.S., Spritzer, P.M.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-03-2005
• Subjects: Adolescent; Adult; Apoptosis; Breast - metabolism; Breast Neoplasms - metabolism; Breast proliferation; DNA, Complementary - metabolism; Estrogen receptor; Estrogen Receptor alpha - chemistry; Female; Fibroadenoma - metabolism; Fibroadenomas; Gene Expression Regulation, Neoplastic; Humans; Middle Aged; Premenopause; Progesterone - metabolism; Proto-Oncogene Proteins c-bcl-2 - chemistry; Proto-Oncogene Proteins c-myc - metabolism; Proto-oncogenes; Reverse Transcriptase Polymerase Chain Reaction; RNA - metabolism; Estrogen receptor; Breast proliferation; Fibroadenomas; Proto-oncogenes; Apoptosis
• ISSN: 0039-128X; 1878-5867
• DOI: 10.1016/j.steroids.2004.10.013

Fibroadenomas are the most common benign lump in females. The study of gene alterations and/or deregulation in reproductive years may help explain hormonal physiological processes involved in nodule development and evolution. The objective was to compare
ER-
α,
c-
myc, and
bcl-
2 gene expression in breast fibroadenomas and in normal tissue and evaluate menstrual cycle, parity, and oral contraceptive influences. Fifty-seven premenopausal women (14–49 years) undergoing surgical removal of fibroadenomas were selected. Samples from fibroadenomas and circumjacent normal tissue were obtained for RT-PCR paired analysis. Patients were divided in groups according to menstrual cycle, use of contraceptives and parity. Tissue from 32 patients was adequate for RT-PCR. Paired analysis showed higher expression of
ER-
α (
P
=
0.012) and
bcl-
2 (
P
=
0.001) in fibroadenomas than in normal breast, while
c-
myc presented a similar expression (
P
=
0.655).
ER-
α was higher in fibroadenomas of patients in follicular phase versus contraceptive users and normal tissue (
P
=
0.003);
bcl-
2 was higher in fibroadenomas of patients in luteal phase than in the normal samples from all groups (
P
=
0.007).
c-
myc did not differ according to menstrual cycle, but was higher in fibroadenomas >3
cm versus <3
cm (
P
=
0.015) and in nulliparous women (
P
=
0.04). A positive correlation between
c-
myc levels and fibroadenoma diameter was demonstrated (
r
=
0.536;
P
=
0.007). Nulliparous mean nodule diameter was superior than parous women (
P
=
0.008). In conclusion, the expression of ER-α, bcl-2 and c-myc depends on hormonal and reproductive factors, with a possible contribution to lump formation and evolution.