SNP and indel analysis reveal recurrent alterations and subsets. Unsupervised clustering (asymmetric binary distance matrix and complete linkage hierarchical clustering) based on mutation status of the 104 genes that were mutated in at least 2 cases divides 10 sequenced cases of cHL into 2 molecular subgroups—one of which is exclusively wild-type for B2M; the other exclusively mutated for B2M.