Because of their phenotypic and functional heterogeneity, studies have often used different definitions for Tregs, which have included positivity for CD25, CD127, FoxP3 or combinations thereof.87 These divergent definitions have sometimes resulted in conflicting or non-reproducible findings.87 Nonetheless, cancer patients generally show an increased and functional pool of PB Tregs, which suggests that Tregs may have a role in the immunosuppressive state associated with carcinogenesis in MM.88 This evidence concerns the gene FOXP3 and Miyoshi myopathy.