OFD1 expression in MM cell lines and primary patient cells. (A) Quantitative mRNA expression level of OFD1 in plasma cells from healthy persons (n = 22), as well as MGUS (n = 44) and MM (n = 12) patients. Box plots define the median values, 25% to 75% of values around the median, and the range of values. *Statistically significant difference among the groups (P < .05). (B) Western blot analysis of OFD1 in MM cell lines and primary patient cells. OFD1 protein expression was analyzed in 12 MM cell lines (MM1s, MM1r, OPM1, OPM2, RPMI8226, U266, INA6, NCIH929, KMS12BM, KMS12PE, KMS11, S6B45), primary tumor cells from 4 MM patients, as well as BMSCs and PBMCs from healthy donors. Levels of OFD1 protein expression are compared with HEK293 and COS7 as positive controls for OFD1 expression.