CDKN1B and neoplasm: These findings lead us to consider that the influence of PBMCs on dysplastic and tumor keratinocyte lineages was positive in stimulating the expression of p27 and thus contributing to cell cycle control and preventing malignant transformation as well as enhancing tumor suppression in the SCC-25 lineage, indicating an anti-tumor influence of PBMCs on different keratinocytes and supporting the concept of immunosurveillance.