GJA1 and esophageal squamous cell carcinoma: However, the expression of Cx43 in ESCC can act as a tumour suppressor or oncogene depending on the malignancy of the tumour; thus, if Cx43-targeted therapy progresses into clinic use, careful quantitative biomarker analysis and a better understanding of how Cx43 mediates cancer phenotypes in different contexts will be required [162].