In addition, several transgenic mice have beenreported to develop multiple myeloma and plasma cell neoplasms7, 8, 9;these mice were genetically modified to trigger the increased expression of genes, suchas c-Myc, XBP-1, and MafB, which have been implicated in theinitiation or progression of myeloma in humans. This evidence concerns the gene XBP1 and plasma cell myeloma.