GRB7 and malignant colon neoplasm: In contrast, to search for unknown genes involved in the MEK-I resistance mechanism, Yu et al. applied CRISPR knockout screening to colon cancer cell lines under MEK-I treatment [17]; they focused on the increased expression of resistance-promoting genes in MEK-I-treated cells by transcriptome analysis and identified GRB7, a gene that confers resistance to MEK-I.