Yin and yang of pluripotency: results of analysis of genes overexpressed in tumor-initiating cells of Krebs-2 ascites carcinoma

Functional analysis of 167 genes overexpressed in Krebs-2 tumor initiating cells was performed. Genes were assigned to the three functional groups that determine the malignant phenotype of cancer cells. These groups represent the following features of tumor cells: proliferative self-sufficiency, invasive growth and metastasis, and multiple drug resistance. Malignancy of cancer stem cells was found to be provided by the same genes that provide the stemness of normal pluri-/multipotent stem cells. These results suggest that the malignancy is just the ability to maintain the stem cell specific genes expression profile, and, as a consequence, the stemness itself regardless of the controlling effect of stem niches.