Importantly, EGF-treated USP21-KO HCT-15 cells developed significantly smaller tumor spheroids compared to EGF-treated Ctrl HCT-15 cells (Fig. 4D, E: USP21-KO HCT-15 treated with EGF vs. Ctrl HCT-15 treated with EGF). The gene discussed is EGF; the disease is neoplasm.