Recently, we discovered that GRP78 contains a nuclear localization signal (NLS) and can translocate to the nucleus in both stressed and malignant cells, where it binds the transcriptional repressor ID2, a basic helix-loop-helix (bHLH) transcriptional factor which functions as a dominant negative inhibitor of E proteins with tumor suppressor properties in lung cancer (17). Here, HSPA5 is linked to lung carcinoma.