CD27 and B-cell chronic lymphocytic leukemia: Of note, our transcriptomic data identified as up-regulated in the PF several genes recently associated with CLL proliferation, such as the C-lectin ligand CLECL1 [45], and the B-cell activation marker CD27, recently reported by Takacs et al. [44] as up-regulated at progression in BTK-mutated CLL cases.