Immunohistochemical demonstration of phosphorylated MEK1/2 and MAPK in malignant and adjacent benign hepatocytes. Human HCCs (T) and ABL tissues (N) were collected and paraffin blocks were prepared as described under Experimental Procedures. 5 μm sections were subjected to immunohistochemical analysis as described under Experimental Procedures. The sections were stained with primary antibody to phospho-MEK1/2 (Ser217/221) (A &B) or mouse anti-phospho-MAP kinase (Thr202/Tyr204) (C &D) antibodies. Original magnification ×400.