Furthermore, transient expression of several mutant p53 forms (p53-G245S, p53-R248W, p53-R249S, and p53-R273H), which lack DNA-binding and transactivation function, in p53-null H1299 human cancer cells had no effect on IRE1α expression; contrarily, only expression of wild-type p53 reduced IRE1α expression (Figure 2C). Here, TP53 is linked to cancer.