Immunohistochemical characterization of cell cycle regulators in non-Hodgkin's lymphoma.

(A) p27 expression analysis in l-MCL demonstrates that the neoplastic cells are negative and that rare intratumor reactive cells show strong nuclear reactivity. (B) The same case also shows overexpression of p53. The expression of Ki-67 (C) in l-MCL and E2F-1 (s-MCL, Panel D) are shown. (E) p27 is highly expressed in resting CLL/SLL cells. However, E2F-1 is detected primarily in proliferating cells of CLL/SLL within proliferation centers (inset; magnification ×400).