HSPA1A and cancer: STAT1, STAT3 (signal transducer and activator of transcription) and NF-IL6/CEBPB are the transcription factors responsible for Hsp70 synthesis in the absence of stress [143,144], as inhibition of both STAT and NF-IL6 activity reduces basal expression of Hsp70 chaperone protein in cancer cells lacking HSF1 or expressing a defective protein [142,145-147].