Since down-regulation of both major cytoplasmic Hsp70s, Hsp70 (HSPA1A, HSPA1B) and Hsc70 (HAPA8) (Figure 1), was necessary to reduce viability of cancer cells from different lines, paralog specificity does not appear to be a desideratum for a clinically usable Hsp70 inhibitor. This evidence concerns the gene HSPA1A and cancer.