These effective CAR-T cell lines differ from the ineffective ones (CAR3-T, CAR4-T, and CAR5-T) only in that their scFvs are derived from other EGFR antibodies, and it can be hypothesized that the unsatisfactory results in ESCC clearance may be due to conformational variations, which may affect binding to EGFR; however, this speculation requires experimental verification. The gene discussed is EGFR; the disease is esophageal squamous cell carcinoma.