Notably, in preliminary studies of array comparative genomic hybridization data from the MMGP, we found that 6/62 (9.7%) patients and 12/48 (25%) myeloma cell lines had decreased copy number of the 12p12.3 region (not shown), suggesting that loss of one PTPRO copy is a not infrequent occurrence in myeloma. Here, PTPRO is linked to plasma cell myeloma.