HSPA5 and leukemia: Furthermore, enrichment of the unfolded protein response gene set, with upregulation of XBP1 (FC 1.95) and HSPA5 (FC 1.42) that were previously demonstrated to be essential for pre-B and pre-B-ALL cells survival38 were detected in the IL7RA-activated and in the leukemia and preleukemia CD10high groups, suggesting a role for early unfolded protein response in the transformation (Fig. 4d, Supplementary Fig. 16, and Supplementary Data 1 and 2).