HER-2 and cancer antigen 125 evaluation in ovarian borderline tumors by immunohistochemistry and fluorescence in situ hybridization

The study determined the expression of cancer antigen (CA) 125 and HER-2 in 45 borderline ovarian tumors (BOTs) and investigated the correlation of these biologic markers with histologic type, clinical stage, and outcome. The level of CA 125 protein was assessed using DAKO's M-11 clone antibody in immunohistochemistry (IHC) assays (Carpinteria, CA). The HER-2 protein expression was assessed in IHC assays using the HercepTest (DAKO), and the HER-2 gene copy number per cell was investigated through fluorescence in situ hybridization (FISH) assays using VYSIS' PathVysion DNA Probe (Downers Grove, IL). Expression of the CA 125 protein was detected in 49% of the samples (22 out of 45 tumors) and significantly associated with the serous histologic type. However, CA 125 expression did not associate with clinical stage or outcome. Protein overexpression or gene amplification of HER-2 was not found. However, abnormal FISH results were detected in 16% (seven out of 45 patients) of specimens comprising extranumerary copies of HER-2 and/or chromosome 17 per cell. Abnormal FISH results were found to be independent of CA 125 expression and histologic type whereas they positively associate with advanced clinical stage. Our data show that HER-2 is not altered in BOTs, and the presence of aneusomy for chromosome 17 and HER-2 may predict tumor progression.