The AEs that occurred most commonly during maintenance treatment with 5FU/LV+anti-EGFR, anti-EGFR, and 5FU/LV were any grade non-hematological (24.6%, 9.1%, and 27.3%, respectively), hematological (22.9%, 7.6%, and 27.3%, respectively), neutropenia (20.3%, 7.6%, and 9.1%, respectively), skin rash (65.3%, 68.2%, and 9.1%, respectively), and paronychia/nail disorders (33.1%, 19.7%, and 0.0%, respectively). The gene discussed is EGFR; the disease is Abnormal nail morphology.