Relationship Study of The Verified Human Epidermal Growth Factor Receptor 2 Amplification with Other Tumor Markers and Clinicohistopathological Characteristics in Patients with Invasive Breast Cancer, Using Chromogenic In Situ Hybridization

Objective Human epidermal growth factor receptor 2 (HER2), as a crucial factor involved in about 20% of breast cancer cases, is one of the most reliable tumor markers to determine prognosis and therapeutic trend of this disease. This marker is generally assessed by immunohistochemistry (IHC) technique. In the cases that result of IHC test cast doubt (+2), the test should be repeated or validated by applying in situ hybridization techniques, like chromogenic in situ hybridization (CISH). In this regard, the goal of current study was to figure out the link between different clinicopathological characteristics of patients suffering from invasive breast cancer, using tumor markers, hormone receptor (HR) and HER2. Comparing IHC and CISH techniques for evaluating diagnostic value and usefulness of HER2 were also the other objective of this study. Materials and Methods Based on this retrospective study, histological markers of 113 individuals suffering from invasive breast cancer such as estrogen receptor (ER), progesterone receptor, HER2 receptor, Ecadherin, CK5/6, vimentin and Ki67 were examined by IHC technique. HER2 amplification of all patients was also evaluated by CISH. Clinicopathological information of the patients was also extracted from medical documents and their associations with tumor markers were statistically evaluated. Results There is a significant relationship between tumor size, CK5/6 and tumor grade with HR status. Similar relationship was observed between HER2 status and HR status, as well as vascular invasion (P 0.05). The comparison of HER2 amplification showed no complete concordance of the result obtained from these two techniques, with score +3. ConclusionSince the status of HER2 is very important in decision making of the treatment process, CISH technique is recommended in the malignant conditions as the primary test, instead of IHC. In this study, we also determined that HER2 expression is greatly correlated with ER and PR status. This might propose a better prognosis for HER2+ patients.