The Journal of pathology
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The Journal of pathology · Aug 2010
Global DNA methylation in fetal human germ cells and germ cell tumours: association with differentiation and cisplatin resistance.
Differences in the global methylation pattern, ie hyper- as well as hypo-methylation, are observed in cancers including germ cell tumours (GCTs). Related to their precursor cells, GCT methylation status differs according to histology. We investigated the methylation pattern of normal fetal, infantile, and adult germ cells (n = 103) and GCTs (n = 251) by immunohistochemical staining for 5-(m)cytidine. ⋯ Furthermore, after demethylation, the stem cell markers NANOG and POU5F1 (OCT3/4), as well as the germ cell-specific marker VASA, showed increased expression. Following treatment with 5-azacytidine, TCam-2 cells were analysed using a high-throughput methylation screen for changes in the methylation sites of 14,000 genes. Among the genes revealing changes, interesting targets were identified: ie demethylation of KLF11, a putative tumour suppressor gene, and hypermethylation of CFLAR, a gene previously described in treatment resistance in GCTs.
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The Journal of pathology · Aug 2010
Barrett's oesophageal adenocarcinoma encompasses tumour-initiating cells that do not express common cancer stem cell markers.
Accumulating evidence has suggested that tumours have a hierarchical organization in which only the cancer stem cells (CSCs) have tumour-initiating properties. Several surface antigens have been employed to isolate CSCs from various malignancies, although not from oesophageal adenocarcinoma (EA). We tested whether Barrett's oesophagus (BE) and EA might serve as a model for the CSC concept. ⋯ No increased tumour-initiating capacity of sorted EA cells was observed upon transplantation. These results indicate that tumour-initiating cells are present in EA, thus reflecting a hierarchical organization. However, antibodies directed against novel surface antigens are needed to detect subpopulations enriched for CSCs in EA by transplantation assays.