Yabe et al., comparing the diagnostic criteria of HSTCL and γδ T-LGL leukemia in 42 patients, revealed that features of absence of splenomegaly, lymphocytes with azurophilic granules, and variable expression of CD5, CD8, CD57, granzyme B, and TCR-αβ were significantly more common in γδ T-LGLL that in HSTCL cases [20]. This evidence concerns the gene CD8A and leukemia.