TP53 and cancer: It has also been confirmed by multiple studies and in multiple cancer types that HSPA9/mortalin interacts with p53 and the regulation of apoptosis by HSPA9/mortalin is TP53-dependent.27, 39, 40 However, the precise mechanism of how HSPA9/mortalin regulates erythroid maturation, especially in del(5q) or 5q− syndrome, is unclear.