ATM and esophageal squamous cell carcinoma: •Contributed to G2/M phase arrest, promotion of apoptosis, and cell migration and invasion•Affected cell invasion, viability, and migration of EMT of ESCC cells through regulation of EZH2‐Notch1 signaling pathway•Dephosphorylation of ATM‐CHK2 pathway, leading to promotion of ESCC growth