HER2 immunohistochemistry in endometrial and ovarian clear cell carcinoma: discordance between antibodies and with in-situ hybridisation.

In ovarian and endometrial CCC, there is considerable difference in HER2 overexpression by different IHC antibodies and marked discordance with ISH. As such, no single antibody can be considered conclusive for determining HER2 status in CCC. Based on these results, the lack of predictive value of different HER2 testing methods, as used in other studies, could be explained.