Activated fibroblasts are common in primary samples from patients with de novo ALL who are undergoing induction chemotherapy. (A) Cytokines and chemokines secreted by MSCs isolated from the normal healthy donor bone marrow or primary patient ALL specimens at diagnosis and after the first and second courses of chemotherapy. IL8 (blue), CCL2 (red), CXCL1 (green), CXCL2 (purple), and IL6 (orange), all in picograms per milliliter, are shown on the y-axis. The x-axis shows each sample denoted by UKALL14 trial patient number (UPN) or healthy donor number (HDN). Arrows below the x-axis indicate the specimens that were subsequently evaluated in more detail. (B) Photomicrographs (original magnification ×40), showing phalloidin and DAPI staining of MSCs isolated from primary patient ALL samples indicated by UPN or HDN. (C) Gene expression profile showing fold upregulation (y-axis) of 18 selected genes in primary patient MSCs (UPN indicated above the panel) at diagnosis (i) and after the first (ii) and second (iii) courses of chemotherapy, compared with the mean baseline of 3 normal healthy donor MSCs, isolated from patients with primary ALL. Red box around UPN indicates specimen with morphological changes. Gene names are shown on the x-axis. A blue line is drawn at twofold upregulation, which is considered significant.