Genomic characterization of five commonly used endometrial cancer cell lines

Recently, the compilation of massive amounts of genetic and genomic information on a wide variety of human cancer types, collectively known as The Cancer Genome Atlas (TCGA), has revealed a wealth of descriptive classification schemes both within and between different types and sources of cancer. In endometrial cancer, TCGA analyses have produced a post hoc scheme composed of four clusters: DNA polymerase epsilon catalytic subunit A (POLE) ultra-mutated (cluster 1), microsatellite instability (MSI) hypermutated (cluster 2), copy-number low (endometrioid, cluster 3) and copy-number high (serous-like, cluster 4). Given that cultured cells are the pre-clinical platform of cancer research, it was questioned how representative endometrial cancer cultured cell lines are in the context of TCGA-driven classification scheme. To address this issue in endometrial cancer cell lines, the present study investigated five commonly used cell lines: Ishikawa, ECC-1, Hec50co, KLE And RL95-2. The histology, mutation profile, MutL homolog 1 promoter methylation, copy-number variation, homologous recombination repair and microsatel-lite instability in each of these cell lines was assessed. The result of this characterization was that none of the cell lines fits neatly into any one of TCGA classes but are still useful models for groups of endometrial tumors. Furthermore, the contention that the ECC-1 cell line is actually Ishikawa was addressed using additional data. It was confirmed that ECC-1 cells likely no longer exist as ECC-1 but that they are not exactly Ishikawa either. For this reason, ECC-1 cells are suggested to be used in vitro but with this caveat in mind. Finally, we compiled a database of 127 endometrial cancer cell lines, including the five reported on here. The wide range of variation found in these cell lines highlights the need to further characterize these cells to select models that are more representative of the various histological and genomic aspects of endometrial cancer.