HSP70 (RM432), RMab

70 kDa heat shock proteins (HSP70) are found ubiquitously in virtually all living organisms, facilitating protein folding and protecting cells from heat stress and toxic chemicals. HSP70 proteins have 3 functional domains: N-terminal ATPase domain, substrate binding domain, and a C-terminal domain that serves as a “lid” for the substrate binding domain. HSP70 binds tightly to partially synthesized peptides and prevents them from aggregating and rendering nonfunctional. HSP70 also inhibits apoptosis by blocking the recruitment of procaspase-9 to the Apaf-1/dATP/cytochrome c apoptosome complex.

HSP70 antibody is shown to be overexpressed in malignant Melanoma and underexpressed in Renal Cell Carcinoma. A variety of tumor cells can express HSP70 with seemingly contradictory functions. Intracellular HSP70 has a cytoprotective function via suppression of apoptosis and lysosomal cell death (LCD) and extracellular HSP70 can promote tumorigenesis and angiogenesis. Other evidence showed intracellular HSP70 can promote apoptosis and membrane-associated/extracellular HSP70 can elicit antitumor innate and adaptive immune responses.

One study evaluated the expression of HSP70 antibody, Estrogen Receptor (ER) and Ki-67 and assessed the relationship between them in Cervical Squamous Cell Neoplasia. It found that HSP70 may play an important role in tumor cell proliferation and is more related with invasive Squamous Cell Carcinoma than Cervical Intraepithelial Neoplasia, but ER may be not related with tumor cell proliferation and differentiation. Therefore, HSP70 may be a useful prognostic factor in Cervical Dysplasia and Cancer.