Western blot analyses corroborate cICAT liquid chromatography–MS/MS studies and show parallel expression in NPM/LK-positive cell lines. (A) The differential expression identified by cICAT liquid chromatography–MS/MS was validated by Western blot analysis using control LacZ (NPM/ALK-negative) and NPM/ALK-transfected Jurkat cells (NPM/ALK positive). Expression of TEK, MKK3, eIF4, Jak2, PTP1B, ephrinB, MAPKAPK, Ki-67, Hsp60, ephrinA, and PP2A was compared with the cICAT ratios shown at the bottom of the Western blots. Histone H1 was used as protein loading control. (B) Up-regulated expression of ALK, and proteins previously reported to be mediators of NPM/ALK (IRS1, GRB2, SHC, Stat3, PI3-K, and PLCg), is corroborated by Western blot analyses. Actin was used as protein loading control. (C) Cell lines derived from NPM/ALK-positive ALCLs (SUDHL-1 and Karpas 299) were used to evaluate the expression of proteins found to be differentially expressed by the cICAT analysis as well as proteins previously known to be regulated by ALK. An ALK-negative ALCL cell line (Mac2A), and NPM/ALK-positive (Jurkat⁺) and NPM/ALK-negative (Jurkat⁻) cells are evaluated in comparison.