title: Increased proliferative background in healthy women with BRCA1/2 haploinsufficiency is associated with high risk for breast cancer.
abstract: Previous studies indicated that BRCA haploinsufficiency was associated with activation of the EGF receptor (EGFR) signaling pathway and increased proliferative activity in mammary epithelial cells of healthy women. We hypothesized that these processes might be reflected in the expression of serologic soluble EGFR (sEGFR) and thymidine kinase 1 (TK1) activity, which signal the initial and final steps of the proliferative pathway, respectively. We found that healthy carriers of BRCA1/2 mutations (n = 80) showed a significantly higher TK1 activity than age-matched controls (P = 0.0003), and TK1 activity was similar in women with BRCA1 and BRCA2 mutations (P = 0.74). The sEGFR concentration was significantly higher in women with BRCA1 than in controls and BRCA2 mutation (P = 0.013 and 0.002, respectively). During follow-up, four of 80 BRCA1/2 mutation carriers developed breast cancer. These women showed a significantly higher TK1 activity and somewhat higher sEGFR concentrations than the other 76 BRCA1/2 carriers (P = 0.04 and 0.09, respectively). All tumors were negative for ovarian hormone receptors, but showed a high EGFR expression. This study was limited by the short-term follow-up (mean, 27 months; range, 5-45), which resulted in a small sample size. Women with BRCA1 and BRCA2 mutations that had undergone risk-reducing bilateral salpingo-oophorectomy (BSO) showed significantly lower sEGFR compared with those without surgery (P = 0.007 and 0.038, respectively). Larger, prospective studies are warranted to investigate whether TK1 and sEGFR measurements may be useful for identifying healthy BRCA1/2 carriers with high risk of developing breast cancer; moreover, sEGFR measurements may serve as effective tools for assessing risk before and after BSO.
authors: Authors' Affiliations: Departments of Oncology, Surgery, and Pathology, Hadassah and Hebrew University Medical Centre, Jerusalem, Israel; and Group of Clinical Virology, Department of Medical Sciences, Uppsala University, Uppsala, Sweden.
authors: Benjamin
authors: B
authors: Nisman
authors: Luna
authors: L
authors: Kadouri
authors: Tanir
authors: T
authors: Allweis
authors: Bella
authors: B
authors: Maly
authors: Tamar
authors: T
authors: Hamburger
authors: Simon
authors: S
authors: Gronowitz
authors: Tamar
authors: T
authors: Peretz
mesh_terms: D000328:Adult; D000368:Aged; D001940:Breast / Q000166:cytology; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology / Q000517:prevention & control; D016022:Case-Control Studies; D048708:Cell Growth Processes / Q000235:genetics; D005260:Female; D019398:Genes, BRCA1; D024522:Genes, BRCA2; D020022:Genetic Predisposition to Disease; D057895:Haploinsufficiency; D006801:Humans; D008875:Middle Aged; D018570:Risk Assessment; D012307:Risk Factors; D015398:Signal Transduction; D016387:Women's Health