HSP70 family members have been suggested as possible targets for therapy of different cancer entities apart from MCC [44]–[46] based on the following observations: HSP70 proteins (i) are overexpressed in cancer cells and/or are induced upon chemotherapy, (ii) possess several cytoprotective and anti-apoptotic functions [47], and (iii) have been demonstrated to be essential for cancer cell survival [19]. This evidence concerns the gene HSPA4 and cancer.