p27 has been implicated as a prognostic factor for a number of tumors, as reduced p27 levels have been observed in cancers of the upper gastrointestinal tract, skin, glioma, sarcoma, and in haematopoietic and epithelial malignancies.85 However, a clear molecular mechanism is yet to be elucidated. This evidence concerns the gene CDKN1B and cancer.