TGFA and keratoconus: Here, we found that KC cells indeed had a lower expression level of TGF-α compared with KPC and TPAC cells (KC: 100.0% ± 53.7%, KPC: 256.5% ± 53.1%, TPC: 389.6% ± 49.5%, TPAC: 413.1% ± 56.5%, Supplemental Figure 4F).