Analysis of signal transduction pathways comparing PCT from C.IL6/iMyc and C.IL6 mice. (A) Schematic overview of signaling pathways chosen for Western blot analyses (B-D). (B-D) Lane numbers correspond to normal splenic B cells (lane 1), PCT from C.IL6 mice (lanes 2-5), PCT from C.IL6/iMyc mice (lanes 6-12, with 3 tumors [lanes 6-8] contained on the blot shown to the left and 4 tumors [lanes 9-12] contained on the blot shown to the right), and commercial positive control (lane 13). Loading of equal protein amounts was documented individually for each Western blot by demonstrating comparable levels of β-actin in all lanes; only one example is shown (D bottom). Pathway screening included IL-6/STAT3/Bcl-X_L (B), RAS/ERK (C), and MYC/p19/MDM2/p53 (D).