Increased JAK/STAT activation in ETP-ALL relative to non-ETP T-ALL. (A) Levels of phosphophorylated (p) and total signaling pathway proteins in the spleens of non-ETP T-ALL xenograft models (ALL8, ALL16, ALL29, ALL30, ALL31, ALL33) and ETP-ALL xenograft models (ETP1, ETP5, ETP8, ETP12, ETP13, ETP14) by immunoblot. A CRLF2-overexpressing B-ALL xenograft with high levels of JAK/STAT pathway proteins was used as a positive control (Control). (B) Comparison of levels of pSTATs and Bcl-2 in non-ETP T-ALL and ETP-ALL xenografts. Protein levels by immunoblot of 3 replicates were quantitated relative to positive control (Control), graphed as means, and analyzed using the nonparametric Mann-Whitney test.