Four genes, RAB10, KLF5, TCF7L2, and CTNNB1 had gene essentiality strongly correlated with both SMAD4 mutation and SMAD4 CNA in various cancer cells (i.e., genes that are more essential when SMAD4 copy number is decreased or when SMAD4 is mutated, P values inferior to 1E-04). The gene discussed is RAB10; the disease is cancer.