HER-2/neu gene amplification in ovarian tumours: a comprehensive immunohistochemical and FISH analysis on tissue microarrays

Aims : Data on HER‐2/neu overexpression, its correlation to prognosis and the success of treatment with Herceptin® in ovarian carcinomas are scarce and contradictory. Therefore we assessed HER‐2/neu expression and amplification in a large series of ovarian tumours by using tissue microarrays (TMAs). Methods and results : Two TMAs containing 173 invasive carcinomas, 36 borderline tumours, 20 granulosa cell tumours, 14 carcinosarcomas, 11 benign cystadenoms and eight other pelvic tumours were constructed to assess HER‐2/neu gene amplification by fluorescence in‐situ hybridization (FISH) and immunohistochemistry. Immunohistochemistry was successful in 94.3%; 81.8% were HercepTestTM negative, 11.3% were scored as 1+, 4.1% as 2+ and 2.8% as 3+, including 3.1% of invasive carcinomas, 2.8% of borderline tumours and 7.7% of carcinosarcomas; 83.6% could be analysed successfully by FISH revealing no aberration in 75.8%, low amplification in 2.7% and high amplification in 3.7% of the cases. In 17.8% monosomy, trisomy, polysomy or deletion could be detected. All cases with high‐level amplification had 2+ or 3+ scores on immunohistochemistry. Conclusions : TMA is a feasible tool to study a large number of ovarian cases. Correlation between immunohistochemistry and FISH was excellent. HER‐2/neu overexpression or gene amplification does not correlate with histological tumour type, stage, grade or prognosis.