CIT is highly expressed in MM patients. (A) Significant increase in CIT in primary BM-derived CD138⁺ MM plasma cells compared with healthy subjects by proteomic analysis using the Antibody Microarray (BD Clontech). (B) CIT gene expression levels in healthy control, newly diagnosed, and relapsed MM patients are shown. (C) Expression of CIT in BM biopsy specimens from MM patients (n = 11) and healthy donors (normal bone marrow [NMB]; n = 6) was detected by immunohistochemistry. Representative slides are shown for each group (original magnification ×20 [left] and ×60 [right]). (D) CIT⁺ cells in immunohistochemistry-stained slides were quantified using ImageJ software (P = .02). (E) Using CIT median gene expression value as a bifurcating point in GSE2658, Kaplan-Meier survival proportions analysis of patient outcome data demonstrates high levels of CIT gene expression associated with inferior OS (P = .01).