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

Steroids. 2005 Mar;70(3):153-60. 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-alpha, 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-alpha (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-alpha 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-alpha, bcl-2 and c-myc depends on hormonal and reproductive factors, with a possible contribution to lump formation and evolution.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Apoptosis
  • Breast / metabolism*
  • Breast Neoplasms / metabolism*
  • DNA, Complementary / metabolism
  • Estrogen Receptor alpha / chemistry*
  • Female
  • Fibroadenoma / metabolism*
  • Gene Expression Regulation, Neoplastic*
  • Humans
  • Middle Aged
  • Premenopause
  • Progesterone / metabolism
  • Proto-Oncogene Proteins c-bcl-2 / chemistry*
  • Proto-Oncogene Proteins c-myc / metabolism*
  • RNA / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction


  • DNA, Complementary
  • Estrogen Receptor alpha
  • Proto-Oncogene Proteins c-bcl-2
  • Proto-Oncogene Proteins c-myc
  • Progesterone
  • RNA