Fig. 4

IL7 stimulates activation of STAT5 in iAMP21-ALL cells with SH2B3 deletion. a Immuno-blot with anti-SH2B3 confirmed loss of expression in PDX of patient 72 that carry a bi-allelic deletion of SH2B3. The full length protein was detected in patients 62 and 69 PDX that showed no evidence for SH2B3 CN or coding sequence abnormalities. MWM (molecular weight marker) with 70 Kd band shown. b Treatment of PDX cells carrying SH2B3 bi-allelic deletion with IL7 resulted in a dose related increase in STAT5 phosphorylation (four flow cytometric immunophenotyping experiments with cells from patient 72) *(P < 0.01) **(P < 0.05). c Analysis of PDX cells expressing wild-type SH2B3 failed to demonstrate any significant increase in STAT5 phosphorylation with IL7 treatment (four flow cytometric immunophenotyping experiments with cells from patient 62 [n = 2] and 69 [n = 2]). P values are for paired t-tests, error bars are standard error of the mean.