HSP90B1 and neoplasm: In addition, expression of both genes was increased 2-fold in MFH19 and also in LMS2x for GRP78, two tumours with similar expression level of ATF6 as the tumours with normal copy number of ATF6. However, the expression level of GRP78 and GRP94 in these two tumours is lower than what is observed in the tumours with over-expression of ATF6, and may possibly be caused by other regulatory mechanisms.