We aimed to compare serum HER2 levels with immunohistochemistry in tumoral tissues and investigate correlation between these levels and various prognostic factors.
This cross-sectional study was conducted on 75 patients with breast carcinoma referred to surgical ward of Mashhad Imam Reza’s hospital from November 2008 to February 2009. Pre-operative serum samples were collected and stored in −20 °C.
Surgical samples were investigated for the type of carcinoma, tumor size, lymph node metastasis, stage as well as grade of the tumor. Tissue HER2 over-expression was evaluated by immunohistochemistry (IHC) staining and HER2 levels were studied by ELISA method. Statistical analysis was performed by SPSS software.
Serum HER2 cut-off level was 18.4 ng/ml; 46.7 % of patients were serum HER2-positive and 43 % were IHC positive. There was a high statistical correlation between these two parameters (P = 0.018).
Statistically, there was no significant correlation between serum HER2 and age, tumor size, stage, grade and metastatic lymph nodes (P > 0.05).
Serum HER2 level assay can be considered as a complementary method besides tissue methods.