Erk activation in follicular lymphoma. (A,B) Tissue lysates of FL (N = 36) and FH (N = 22) were printed on RPMAs and probed with antibodies for Erk (A) and phosphorylated Erk on Thr202/Tyr204 (B), as described in “Methods.” Scatterpoints represent relative signal intensity averaged over 3 runs and are depicted on a log10 scale. Median group values for FL and FH are designated with horizontal bars on the scatterplots and are listed beneath each plot, with the P value for comparison of the 2 groups. FL samples representing grade 3B are indicated by ○. (C) A total of 6 samples of FL (G1 indicates grade 1; G2, grade 2; G3, grade 3A) were compared with 3 samples of FH on Western blot, using antibodies for detection of total Erk and phospho-Erk Thr202/Tyr204. Serum-starved HeLa cells (0) and HeLa cells treated with epidermal growth factor (+E) served as negative and positive controls for Erk activation. L represents the lane used for the molecular weight ladder.