TRIB1 (but not TRIB3) functionally resembles TRIB2 in this phenotypic mouse cancer model, since it also degrades C/EBPα and causes highly penetrant AML (Figure 5), in line with a postulated TRIB evolutionary pathway that led linearly between TRIB2 and TRIB1 and, hence, on to TRIB3 (Figure 2) and the high level (71%) of amino acid similarity between TRIB1 and TRIB2 within the pseudokinase domain. Here, RIBC2 is linked to acute myeloid leukemia.