Figure 2.

Impact of multiple myeloma on the mesenchymal stromal cell transcriptional program according to minimal residual disease status. (A) Principal component analysis (PCA) of gene expression profiles from mesenchymal stromal cells (MSC) from patients with multiple myeloma (MM) at the time of diagnosis and matched samples during minimal residual disease (MRD). Data for PCA were transformed to account for the paired design. Gene expression dispersion was measured as mean absolute deviation (MAD). (B, C) Volcano plot of differentially expressed genes in MSC during the stage of MRD positivity. Paired differential expression analysis showed that three genes were downregulated in MRD⁺ MSC compared to their counterpart MSC at diagnosis of MM (B) and 56 were deregulated in MRD^–MSC compared to the counterpart MSC at MM diagnosis (C). (D) Semi-supervised k-mean clustering (k=4) of genes significantly up- or down-regulated in (B) and (C). Adjusted P<0.1 and |log²FC| >1.