Expression of phosphorylated ERK1/2 and MYC in vivo. Immunohistochemical analysis of MYC (A,C) and phospho-ERK1/2 (B,D) in 2 CLL/SLL lymph node biopsy samples. The images show expression within representative PCs comprising larger, less densely stained cells. (E-F) MYC expression in Burkitt lymphoma and phospho-ERK1/2 expression in colon cancer, respectively. Original magnification ×600.