Additionally, higher expression of TIGIT in CLL groups with stages 1 and 2 compared to stage 0, according to the Rai classification, as well as in CLL groups in the 1, 2, 3 and 4 stages compared to stage 0 was observed, which might suggest the more important impact in the more developed disease. This evidence concerns the gene TIGIT and B-cell chronic lymphocytic leukemia.