FGF4 and prostate cancer: Copy number alterations are common genetic alterations that contribute to gene dysregulation in ESCC.34, 35 Some of the previously observed CNAs include amplification of 11q13.3 (FGF4), 3p26.33 (SOX2OT), 8q24.21 (MYC), 14q21.1 (FOXA1) and deletion of 9p21.3 (CDKN2A).35 Some tumour suppressor genes in 8p21 were down‐regulated as a result of deleted chromosomal region, such as BNIP3L in breast and ovarian cancer36 and NKX3.1 and miR‐3622b in prostate cancer.37, 38 This triggered our interest to explore the association between the CNA status of PDLIM2 and its expression in ESCC.