The Molecular Profile Of Breast Cancer Patients According To The Presence Of Her2 Overexpression.

e23150 Background: Overexpression of the oncogene HER2/neu (c-erbB-2) occurs in up to 30% of breast cancers and is correlated with worse survival, especially in node-positive patients. The aim of this study was to evaluate the association between genes such as BRCA1, BRCA2, CHEK2, NOD2, TP53 and HER2 overexpression in breast cancer patients (pts). Methods: We reviewed the medical records of 118 breast cancer patients with HER2 positive tumors (HER2 overexpression or amplification) who were treated with trastuzumab in COI. The control group (129 patients) was chosen from breast cancer pts with HER2 negative tumors. Mutation profile was assessed by PCR technique. We evaluated the presence of BRCA1 (c.5266dupC), (c.68_69delAG), (c.181T > G), (c.4034delA), BRCA2 (c.9403delC), (c.5946delT), CHEK2 (c.470T > C), (c.1100delC) and NOD2(c.3016_3017insC), polymorphism TP53 (c.[215G > C]). In statistical analysis Fisher’s exact test were used for categorical variables to determine differences between groups. Results: In the group with HER2 overexpression 15 (13%) pts were mutation carriers. The most commonly detected mutation was 215G > C TP53. It was observed in 8 (6.8%) of pts. Six (5.1%) pts were CHEK2 mutation carriers (4% I157T carriers and 0.8% 1100delC carriers). Only one woman had 3020insC NOD2 mutation. No one in analyzed group had BRCA1/2 mutation. In control group (HER2 negative pts) 83 (64%) pts were mutation carriers. The most commonly detected mutations in this group were BRCA1/2 (n = 43; 33%) and CHEK2 (n = 38; 29%), (28.7% I157T carriers and 0.8% 1100delC) carriers. Only 2 (1.6%) pts had polymorphism TP53. No one of them has NOD2 mutation and 215G > C TP53. Polymorphism TP53 was detected more frequently in HER2 positive group than in HER2 negative pts (6.8% vs 1.6%), p = 0.05. CHEK2 mutation was present more often in pts without HER2 overexpression (29.5% vs 5.1%), p = 0.0001. Conclusions: HER2 overexpression in breast cancer tumor was associated with the presence of 215G > C TP53 polimorfizm. In the group of pts with HER2 negative tumor BRCA1/2 and CHEK2 mutations were more often observed than in HER2 positive tumors. Further studies on a larger group of patients are necessary.