IFNB1 and colorectal carcinoma: When mismatch repair-deficient (MMRd) and MMR-proficient (MMRp) CRC samples were compared, IFNβ expression in cluster 3 and cluster 4 CD4+ T cells (positive for CXCL13) was found to be significantly greater in the MMRd tumor samples (Fig. 7J, K and Supplementary Fig. 10D).