The novel compHsp70 sandwich ELISA is based on two mAbs, cmHsp70.1 and cmHsp70.2, recognizing conserved epitopes in the C-terminal substrate binding domain of inducible Hsp70 [40,41] and allowing a specific and sensitive quantification of both, free and vesicular Hsp70 in the blood of patients with cancer. The gene discussed is HSPA1A; the disease is cancer.