Aim: Breast cancer is the most common cancer in women affecting one in eight in their lifetime [1]. HER-2 gene is amplified in approximately 20-40% of breast cancers [2], which correlates with aggressive disease and amenable to treatment with Trastuzumab. The aim of this study is to detect amplification of HER-2 gene by chromogenic insitu hybridization (CISH) and HER-2 protein by immunohistochemistry in Manual Tissue microarray sections of breast cancer. Materials and Methods: 30 confirmed breast cancer cases were included in the study in which adequate tissue material were available. The breast tissue fixed in 10% buffered formalin were routinely processed and HE stained slide obtained for confirmation of tumour tissue in the paraffin block. A total of 2 Tissue microarray blocks were made each having 15 cores each from different patients using the method described by Singh et al . Sections were taken from each microarray block for HE staining, CISH and IHC study. Results: 20% showed HER-2 protein positivity. 23% were found to be positive for HER-2 gene. Cohens kappa calculated to find the degree of agreement between the HER-2 protein expression detected by IHC and HER-2 gene expression detected by CISH in Tissue microarray sections is 0.510, which indicates moderate agreement. Conclusion: We conclude HER-2 expression in carcinoma breast could be studied by IHC and CISH with ease on Tissue microarray sections, a cost effective method which can be used for both research and diagnostic purposes in resource limited laboratories.

Keywords: Breast Cancer; HER-2/neu; Chromogenic Insitu Hybridization; Immunohistochemistry; Manual Tissue Microarray.