Thus, our and previous findings support ZEB1 as a strong candidate tumor suppressor gene in CTCL as already described in ATLL;20 differently from canonical cancer genes like TP53, PTEN, RB1, and CDKN2A recurrently inactivated also in other cancer types, ZEB1 seems to be a lineage-specific tumor suppressor. This evidence concerns the gene RB1 and primary cutaneous T-cell non-Hodgkin lymphoma.