CDKN2C and neoplasm: Based on the results of the present study where ectopic expression of p18 in mouse ES cells enhanced the cell growth and stemness by up-regulating self-renewal genes and down-regulating differentiation genes, it further reinforces the notion that cell cycle regulation in ES cells is distinct from that in somatic cells and cell cycle regulators have distinct effects on ES cells vs. somatic cells including adult stem cells and tumor cells.