PIK3CA and esophageal squamous cell carcinoma: Due to recent advances in next generation sequencing (NGS) technology, which has facilitated analysis of the whole genome, exome and target sequences, a great deal of information on the aberrations of cancer-related genes causing the development and progression of ESCC has accumulated, and this has led to the description of the landscape of ESCC-related somatic aberrations, such as TP53, CDKN2A, NOTCH and PIK3CA [3–8].