TLS with primary (CD21+ follicular dendritic cells [DCs]) and secondary (CD21+CD23+ follicular DCs) follicles were defined as mTLSs, using criteria previously employed for lung carcinoma, colorectal carcinoma and melanoma (Fig. 1A, Supplementary Fig. 2B, C)43–45. The gene discussed is CR2; the disease is colorectal carcinoma.