GJA1 and squamous cell carcinoma: For example, E-cadherin, a prominent epithelial marker, was reported to preserve the functional membrane-associated gap junctions comprising different connexins in non-transformed epithelial cells (Cx43) [48], in human squamous carcinoma (Cx43) [49], and in colorectal cancer (Cxs 26, 32, 43) [50].