HSP90B1 and cancer: Our novel observation that GRP78 and GRP94, both with primary residence in the ER, can colocalize in the nucleus of the stressed and cancer cells suggests that ER stress activates a yet to be defined process in the ER that enables GRP78 efflux to the cytosol and entry into the nucleus, where it forms complex with GRP94 which also traffics to the nucleus upon ER stress.