Grp78 expression in leukemia and relapse in childhood ALL. (A) Grp78 mRNA levels measured by RT-PCR from peripheral blood or BM (*) samples of the indicated types of leukemia patients, with β-actin levels as control. Below is a summary of Grp78 transcript level in an expanded study after normalization against β-actin. (B) GRP78 protein expression in Ficoll-Paque isolated peripheral blood mononuclear cells of normal control and leukemia patients (AML, CML, ALL, and CLL). Below is the quantitation of the relative GRP78 level normalized against β-actin. (C) Comparison of Grp78 expression between normal BM (n = 5) and AML patient samples (n = 285) using microarray database. (D) Grp78 expression level determined from microarray database of relapse ALL patients (n = 60) was plotted against time to relapse. The horizontal bar represents median Grp78 expression (456) of all ALL patients; and the vertical bar at the 36-month time point separates patients with early relapse (left) and late relapse (right). *P < .05 (Student t test). **P < .01 (Student t test).