PKM and esophageal squamous cell carcinoma: In addition, our previous study 7 confirmed that PKM2 was highly expressed in ESCC tissues and PKM2 was highly expressed in KYSE150 cell line and low expressed in Eca109 cell line, so lentiviral transfection was used to silence PKM2 in KYSE150 cell line and overexpress PKM2 in Eca109 cell line.