PRKCB and adult T-cell leukemia/lymphoma: Consistent with the non-involvement of T-cells in the EMH phenotype and despite the PKCβ D427N mutation being frequent in ATLL, there is a limited impact of the mutant knock-in on the T-cell repertoire, the only significant distinction being in the apparently transient down-regulation of the TCRβhigh population in the 12-week-old cohort of heterozygous mutant mice.