Material and Methods: Cyclin D, E, A, and B, and cyclin-dependent kinase inhibitor (CDKI) p16 and p21 levels weremeasured via flow cytometry in patients with chronic myeloid leukemia (CML) (n = 16) and multiple myeloma (MM)(n = 13), and in controls (n = 15). This evidence concerns the gene CDKN2A and plasma cell myeloma.