Her2/neu gene amplification in breast carcinoma patients: Our experience with fluorescence in situ hybridization (FISH) technique

BackgroundIn India the incidence of breast cancer has increased in the urban population with 1 in every 22 women diagnosed with breast cancer. It is important to know the Her2/neu gene status for a better prognostication of these patients.AimThe aim of study was to compare the efficacy of fluorescent in situ hybridisation (FISH) and immunohistochemistry (IHC) for determining Her2/neu alteration in breast carcinoma.Material & methodsA total of 188 histologically proven breast carcinoma cases between years 2007–2011 and were retrospectively analysed on the paraffin tissue sections by both IHC & FISH techniques. FISH for Her2/neu gene amplification was performed on cases where the IHC status was already known and the results were compared.ResultsA total of 64 (30%) patients were found to be amplified and remaining 124 (65.9%) cases were found to be unamplified through FISH. Patients observed with 3+ reading on IHC were later confirmed as unamplified in 29.5% cases through FISH.Interpretation & conclusionIt has been confirmed with the present study that IHC is a prudent first-step technique to screen tissue samples for Her2/neu gene status but should be supplemented with the FISH technique especially in equivocal cases.