BCR and B-cell chronic lymphocytic leukemia: Diving into U-CLL subgroup, cases carrying identical BCR belonging to an aggressive subgroup of the disease called stereotyped subset #8 were found to be distinct using PCA and hierarchical clustering in different single omic modalities, i.e., gene expression, DNA methylation, and histone modifications (Papakonstantinou et al., 2019; Tsagiopoulou et al., 2023).