In this study we have identified upstream regulation of differentiation as a substantial difference between EC and ES cells, supporting our hypothesis. While down regulated mEC and mES genes displayed similarity, upregulated SCC PSA1 genes were almost 90% specific to malignancy. This supports a model where normal and malignant stem cells employ similar mechanisms to maintain the self renewal state. The different phe notypes developing from differentiation, therefore, are related to activation of specific malignant or non malignant genes. Both cell types alter genes related to similar processes, receptor mediated signalling of development differentiation. Thus the differentiation of malignant and non malignant cells is driven by a diver gent group of genes.

It is noteworthy that the primary recurrent genetic switch contained an equally strong Nulli SCC cell signature, despite the additional reading much reduced genelist. Nulli SCC cells avoid differentiation through maintained levels of gene and miRNA expression to generate highly malignant tumors. While a small number of molecular events take place in these cells response to differentiation, these appear to have a par ticular relevance to the difference between primary and recurrent disease. Stemness genes are never expressed by recurrent disease only, suggesting a less stem like profile. These genes have a particular relevance to cel lular proliferation and apoptosis, including p53 p21 regulation. Of particular note is the downregulation in Nulli SCC cells of TLR signaling adapter Tirap, a gene that is constantly expressed in primary and recurrent disease.

TLR signaling has received increased attention {buy inhibitor| selleck chemicals|selleck|selleck chemicals|LDC000067 in both cancer and stemness studies in recent years. In summary, recurrent disease appears to have more correlation with nullipotent cells rather than EC cells with good differential potential. Recurrent tumor development involves the suppression of twice as many genes as are specifically activated. This indicates that recurrent malignancy does not require a substantial number of mechanisms employed by primary tumors. Specifically, angiogenesis and development genes are turned off by recurrent dis ease as malignancy genes are turned on. The upregula tion of polycystic ovary associated gene Fabp4 and ovarian cancer gene Prkcbp1 may be of particular impor tance. There was little overlap between genes altered in cohort 1 and cohort 2, which altered genes more asso ciated with malignancy and less with differentiation. Functional relationship analysis revealed that recurrent disease no longer requires homeostasis or stimulus response processes while upregulating catalytic activity and protein binding process.