CD4 and T-cell leukemia: mRNA sequencing in adult T cell leukemia/lymphoma, cutaneous cytotoxic T cell lymphoma, and CD4+ primary human T cells has revealed a third transcript (transcript 3) not reported in Ensembl (Park et al., 2017; Uchida et al., 2021), encoding a 1399-amino acid protein with 39 exons (isoform 3).