[Determination of receptor and HER2 status of breast cancer using tissue matrix technology. Validation of the method]

We studied ability of TMA technique as alternative to analysis of whole sections (WS) for breast carcinomas. The study included 229 patients with breast carcinoma T1-2 N0 M0 treated within 2000-2009 years. After whole slide scanning were constructed TMA blocks using 2mm punches and TMA master device (3DHistech, Budapest). TMA results of immunohistochemistry of HER2 were compared retrospectively with the results of WS. General distribution of HER2 status for WS was: negative (0+1) 85,5%, unequal (2+) 6,07%, positive (3+) - 8.41%, for TMA cores negative (0+1) 82,6%, unequal (2+) 7,04%, positive (3+) - 10,33%. When we compared each cases for HER2 there was moderate agreement with negative (score 0) and positive(score 3+) case around 70% and poor agreement in HER2 (1+2+ category) - only 50% 25% including both false negative and false positive estimations. We thought such kind disagreement in individual group was due to using different primary antibodies (all not FDA-approved) in previous years compared with PATHWAY® rmAb 4B5 (Ventana) antibody which was used for TMA slides. For breast cancer TMAs could be reasonable alternative to WS. Especially for Her2 testing, should be used only FDA approved systems and this technique allow reduce time, reagent and finally cost of such type of analysis.