As p53 is crucial not only for preventing abnormal cell proliferation, but also for suppressing other aspects of tumorigenesis, including tumor angiogenesis, metabolic reprogramming, tumor metastasis, and prevention of apoptosis, these facts indicate that the XBP1-u/MDM2/p53 axis might also be involved in the regulation of these hallmarks of cancers. This evidence concerns the gene XBP1 and cancer.