PTPRO and B-cell chronic lymphocytic leukemia: In contrast, this same group studied the effect of PTPROt downregulation in Eμ-TCL1A mice by inactivating a single (heterozygous knockout [HET]) or both (homozygous knockout [ROKO]) PTPROt alleles in wild-type (WT) and Eμ-TCL1A mice to determine how it impacts CLL onset in these mice.