KRAS and acute lymphoblastic leukemia: Single-cell sequencing has made it possible to measure the clonal structures of childhood acute lymphoblastic leukemia (ALL) samples at diagnosis, and to establish the sequence of genetic events that underlie the disease; first, most of the structural variants, followed by single-nucleotide variants (SNVs), with KRAS (Kirsten Rat Sarcoma Viral Oncogene Homolog) mutations occurring late in disease development [32].