a, BCR (magenta) puncta expression at the single-cell level on CD20 (green) expressing OCI-LY10 in the presence or absence of CD40L-stromal cells, with DAPI (blue). Data representative of n = 5 hydrogels for each condition. b, Median fluorescent intensity (MFI) of MALT1 in human ABC-DLBCL PDX cells cultured in ±CD40L-stromal cell conditions for 96 h. Two-tailed unpaired t-test between two groups within a cell line (mean ± s.e.m., n = 3, where each dot is a hydrogel-based organoid). c, MFI of MALT1 in human ABC-DLBCL cell lines cultured in ±CD40L-stromal cell conditions for 96 h. Two-tailed unpaired t-test between two groups within a cell line (mean ± s.e.m., n = 4, where each dot is a hydrogel-based organoid).