HSF4 and breast cancer: Although there are only a few studies reporting on the expression of HSF2 and HSF4 in cancer, decreased expression of HSF2 has been shown in epithelial cancers, such as prostate and breast cancers as well as small-cell lung carcinomas, whereas low-grade gliomas, lung cancer tissue, and esophageal squamous cell carcinoma (ESCC) display high HSF2 expression [88,91,92,93].