“…Several proteins that regulate the mitotic cycle, such as cyclin D1, D3, E, B1, cyclin-dependent kinases 1, 2 and 6, S-phase kinase associated protein-2, p16 INK4A , p18 INK4c , p21 CIP1 , p27 KIP1 , p53, the retinoblastoma protein and PCNA have been found to be deregulated in classical Hodgkin's lymphoma. [1][2][3][4]6,[20][21][22][23][24][25][26] In the present study, we used a previously validated classical Hodgkin's lymphoma tissue microarray with a cohort of clinically well-documented cases 6,17,27 to analyze the expression of the cyclin-dependent kinase inhibitors of the Cip/Kipfamily, p21 CIP1 and p27 KIP1 , as well as two proliferation markers, PCNA and cyclin A. Since Hodgkin and Reed-Sternberg cells are embedded within reactive normal lymphocytes, we used those lymphocytes as internal controls for our staining Aberrant cell cycle regulation in Hodgkin's lymphoma A Tzankov et al conditions.…”