Background: Upregulation of Heath
Shock Protein 70 (HSP70) chaperones supports
cancer cell survival. Their high homology causes a challenge to differentiate them in experimental or prevention and treatment strategies. The objective of this investigation was to determine similarities and differences of Hsp70, hsc70,
Grp78 and
Mortalin members of the HSP70 family encoded by HSPA1, HSPA8, HSPA5 and HSPA9 genes, respectively. Methods: Literature reviews were conducted using HSPA1, HSPA5, HSPA8 and HSPA9 gene or
protein names or synonyms combined with biological or
cancer-relevant terms. Ingenuity Pathway Analysis was used to identify and compare profiles of
proteins that directly bind individual chaperones and their associated pathways. TCGA data was probed to identify associations of hsc70 with
cancer patient survival. ClinicalTrials.gov was used to identify HSP70 family studies. Results: The chaperones have similar protein folding functions. Their different cellular effects are determined by co-chaperones and client
proteins combined with their intra- and extra-cellular localizations. Their upregulation is associated with worse patient prognosis in multiple
cancers and can stimulate
tumor immune responses or drug resistance. Their inhibition selectively kills
cancer over healthy cells. Conclusions: Differences in Hsp70, hsc70,
Grp78 and
mortalin provide opportunities to calibrate HSP70 inhibitors for individual
cancers and combination
therapies.