CDKN2A and esophageal squamous cell carcinoma: For example, objective response and progression‐free survival (PFS) rates were found to be higher in ESCC patients with CCND1, FGF3, FGF4, and FGF19 amplification than in those without [13], and a recent study proposed a combined prognostic model for ESCC progression and metastasis consisting of KMT2D mutation; CCND1, FGF3, FGF4, and FGF19 amplification; and CDKN2A deletion [14].