Seminoma and embryonal carcinoma footprints identified by analysis of integrated genome-wide epigenetic and expression profiles of germ cell cancer cell lines (ChIP-seq data).

Background: Germ Cell Cancers (GCC), originating from Primordial Germ Cells /gonocytes, are the most common cancer in young men, subdivided in seminoma (SE) and non-seminoma (NS, stem cell component: embryonal carcinoma (EC)). Somatic mutations are rarely found in GCC. It has been proposed that disruption of the epigenetic constitution, either primarily or secondary (e.g. environmental influences), is involved in cancer, and specifically in GCC.Results: This study aims at identifying epigenetic footprints of SE and EC cell lines in genome-wide profiles by studying the interaction between gene expression, DNA CpG methylation and histone modifications, and their function in GCC and related disruption of germ cell maturation. Two well characterized GCC-derived cell lines were compared, one representative for SE (TCam-2) and the other for EC (NCCIT). Data was acquired using the Illumina HumanHT-12-v4 (gene expression) and HumanMethylation450 BeadChip (methylation) microarrays as well as ChIP sequencing (activating histone modifications (H3K4me3, H3K27ac)). The data show that known germ cell markers are not only present and differentiating between SE and NS at the expression level, but also in the epigenetic landscape.Conclusion: The overall similarity between TCam-2 / NCCIT supports an erased embryonic gem cell arrested in early gonadal development as common origin. Subtle difference in the (integrated) epigenetic and expression profiles indicated TCam-2 to exhibit a more germ cell like profile (enrichment Androgen regulation) while NCCIT proved more pluripotent. The results provide insight into an integrated analysis of the functional genome in GCC cell lines.