Oral Keratinocytes (OKs)

A keratinocyte is the predominant cell type in the epidermis, the outermost layer of the skin, constituting 90% of the cells found there. Those keratinocytes found in the basal layer (stratum basale) of the skin are sometimes referred to as "basal cells" or "basal keratinocytes". Oral keratinocytes（OKs）display a restricted replicative life span in cell culture. Those cells initially proliferate but eventually enter a state of permanent growth arrest, called replicative senescence, which is clearly distinct from terminal differentiation.Oral keratinocytes express a variety of differentiation markers, the expression of which is influenced by calcium-induced changes in the transcription of target genes. Some results indicate overexpression of cyclin D1 together with a dominant-negative form of p53 led to the immortalization of oral keratinocytes at high frequency through a telomerase-independent ALT mechanism.