Since we have previously showed that AMPK suppresses the UPR in ALL [19], and others had reported that metformin can inhibit the UPR in normal renal tubular epithelial cells and certain carcinomas [38,39], we determined the effects of metformin on the expression of UPR markers in cell lines and primary ALL cells. This evidence concerns the gene PRKAA1 and acute lymphoblastic leukemia.