HSF1 and cancer: In addition to its transient activation in the classical heat shock response, HSF1 is frequently upregulated in human cancers.4,6–8 An HSF1-regulated transcriptional program has been identified that is specific to highly malignant cells, overlapping with but distinct from the heat shock response, which is strongly associated with metastasis and poor survival in cancer patients.9 There are multiple mechanisms by which HSF1 has been proposed to facilitate oncogenesis.