Progressive increase in MARCH5 gene expression along the course of disease progression to myeloma and strong correlation between MARCH5 and survival in MM. (A) MARCH5 gene effect across different cancer types. MARCH5 has a much lower gene effect size in several MM cell lines when compared with other malignancies, indicating that it serves a more essential role in MM than in other cancer types. (B) MARCH5 is among the top 20 dependencies enriched in MM cell lines. (C) Strong correlation between MARCH5 and patient survival in MM. The results of the association between MARCH5 and survival in MM are shown for the CoMMpass and HOVON data sets. The univariate Cox regression results that used MARCH5 expression profiles are shown at the top of each plot and log-rank test results overall and between any 2 of 3 patient groups (top 25% [T25], middle 50% ([M59], and bottom 25% [B25]) based on MARCH5 expression levels are also shown. (D) Progressive increase in MARCH5 gene expression along the course of disease progression to myeloma (and beyond) in the Italy data set. Significance, determined using the Wilcoxon’s test, between the respective disease stages and normal is indicated at the top of each stage as follows: ∗.01 < P ≤ .05; ∗∗.001 < P ≤ .01. (E) IHC staining was performed using anti-MARCH5 antibodies on the TMA slides collected from the tissue repository section of the Department of Pathology, NUH, Singapore. (F) Representative images of MM tissue stained using mIHC staining (MARCH5, green; CD138, red; DAPI, blue), displaying regions with no MARCH5 expression and regions with MARCH5⁺, CD138⁺, and MARCH5⁺CD138⁺ expressions. Images in the top row have a original magnification of 100×, whereas the images in the bottom row are a selected zoomed-in region with an original magnification of 300×. (G) The mIHC-based quantification of the average proportion of MARCH5⁺ cells in a MM TMA cohort (n = 75) in comparison with that in a tonsil sample (n = 1). NUH, National University Hospital.