Cas9 and sgRNA-directed selective and efficient disruption of mutant KRAS in cancer cells. Cas9 and sgRNAs were delivered into cancer cells and the indel frequencies at the endogenous target sequences were evaluated by deep sequencing. Untreated cells were used as the control. The names of the cancer cell lines and their related mutations are shown at the top of each graph. (Hetero.) Heterozygous, (Homo.) homozygous. (A–F) Indel frequencies in cancer cells after delivery of Cas9 and sgRNA. Error bars represent SEM. (G) Average sequence frequencies. The values from each experiment are shown in Supplemental Figure S6. Red = Indels, green = wild-type KRAS (unedited), purple = mutant KRAS (unedited).