KRAS and juvenile myelomonocytic leukemia: Over 90% of JMML driver mutations involve five genes in the canonical RAS pathway (PTPN11, NRAS, KRAS, NF1, CBL), with approximately 35% being somatic PTPN11 (gain of SHP-2 function) exon 3 or 13 mutations [133,189,190,204,205,224,225,226,227,228,229].