HSF1 and neoplasm: In a study on pancreatic tumorigenesis, HSF1 silencing led to the upregulation of pro-apoptotic proteins, including SMAC, cytochrome c, Apaf1, and cleaved caspase-3 and -9, suggesting that HSF1 inhibits the mitochondrial apoptosis pathway to promote tumor growth (Liang et al., 2017).