HSPA1A and prostate carcinoma: These results support a non-classical secretory pathway for HSP70 and are consistent with its lack of a consensus signal sequence and with previous studies from the Calderwood group that showed an endolysosomal mechanism involving the ATP binding cassette (ABC) family transporter proteins in the secretion of HSP70 from PC-3 and LNCaP human prostate carcinoma cell lines [52].