Effect of brentuximab-vedotin on proliferation and cell cycle distribution in neoplastic MCs. (A-B) Primary BM cells obtained from 3 patients with CD30⁺ SM (ASM, n = 1; MCL, n = 2; A, left panel), 3 patients with CD30⁻ SM (ISM, n = 1; ISM-AHNMD, n = 1; MCL, n = 1; A, right panel), and cell lines (MCPV-1.1, MCPV-1.4, HMC-1, C2) (B) were incubated in control medium (Co) or in various concentrations of brentuximab-vedotin (0.1-50 µg/mL) at 37°C for 96 hours. After incubation, ³H-thymidine uptake was measured. Results represent the mean ± SD from 3 independent experiments. *P < .05. (C) MCPV-1.1 cells were incubated in control medium (Co) or in brentuximab-vedotin (20-50 µg/mL) at 37°C for 1 hour. After incubation, cells were washed and injected into the tail vein of NSG mice (3 × 10⁶ cells/per mouse, 5 mice per group in 3 independent experiments). After 5 weeks, mice were sacrificed and MCPV-1.1 repopulation was measured by determining the percentage of CD45⁺/CD117⁺ cells in mouse BM samples by flow cytometry. Results represent mean ± SD from all mice in all experiments. *P < .05. (D) HMC-1.1 cells (top, left panel), HMC-1.2 cells (top, right panel), MCPV-1.1 cells (middle, left panel), MCPV-1.4 cells (middle, right panel), and C2 cells (bottom panel) were incubated in control medium or in various concentrations of brentuximab-vedotin (2.5-10 µg/mL) at 37°C for 96 hours. Then, cell cycle distribution was analyzed by flow cytometry. Results show relative cell numbers and represent the mean ± SD from 3 independent experiments. *P < .05.