Comprehensive analysis of PD-L1 expression, HER2 amplification, ALK/EML4 fusion, and mismatch repair deficiency as putative predictive and prognostic factors in ovarian carcinoma.

Most ovarian carcinomas (OC) are characterized by poor prognosis, particularly the most frequent type high-grade serous carcinoma. Besides PARP inhibitors, target-based therapeutic strategies are not well established. We asked the question which other therapeutic targets could be of potential value and, therefore, analyzed a large cohort of OC for several predictive factors. Two hundred eighty-eight (288) cases of OC including the major histological types were analyzed by immunohistochemistry for PD-L1HER2, ALK, and the mismatch repair (MMR) proteins MLH1, PMS2, MSH2, and MSH6. HER2 amplification and ALK/EML4 fusion were assessed by fluorescence in situ hybridization. The most frequent finding was PD-L1 expression ≥ 1% in 19.5% of the cases, which correlated with a significantly better overall survival in multivariate analysis (p < 0.001). HER2 amplification was detected in 11 cases (4%), all high-grade serous carcinomas. Amplification of HER2 did not correlate with patients' survival. ALK/EML4 fusion was found in two cases (0.74%): one high-grade serous and one endometrioid carcinoma. MMR deficiency was only present in one case of stage IV high-grade serous carcinoma. Subsets of high-grade serous carcinomas show PD-L1 expression and HER2 amplification, respectively, and, therefore, could qualify for immune checkpoint inhibitor therapy or anti HER2 therapy. PD-L1 is also of prognostic impact. ALK/EML4 fusion is very rare in OC and not a putative therapeutic target.

Analysis of gene amplification and prognostic markers in ovarian cancer using comparative genomic hybridization for microarrays and immunohistochemical analysis for tissue microarrays.

To identify oncogene amplification involved in ovarian carcinogenesis, we studied 21 ovarian carcinomas and 5 serous borderline tumors using conventional comparative genomic hybridization (CGH) and CGH to a genomic DNA microarray. Immunohistochemical analysis of the proteins encoded by the genes that were amplified frequently (FGF3/4, FGFR1, CCNE1, PAK1, JUNB, and MDM2) was performed on a tissue microarray comprising 254 cases of ovarian neoplasms. Regarding histologic type, characteristic patterns of copy number changes were revealed. They correlated with histologic tumor type and with intratumoral heterogeneity. Gain of FGF3/4 and CCNE1 was found in all serous carcinomas. Endometrioid carcinomas most frequently showed gain of JUNB (83%), KRAS2 (67%), MYCN (50%), ESR (50%), and CCND2 (50%). Of the serous borderline tumors, 80% harbored amplification of FGFR1 and MDM2 and a 75% gain of PIK3CA. Only CCNE1 immunoreactivity was significantly correlated with CGH results (P < .05) and postoperative survival (P < .05). Microarray-based genomic analysis in combination with immunohistochemical analysis was found to be a powerful technique for identification of clinically relevant gene amplification in human ovarian cancer.