GJA1 and cancer: Because in this work we use a purely functional approach, we cannot determine the types of connexins involved in the increase in ouabain-induced GJIC, or even if the mechanisms involved are common to all types of cancer cells tested here but, in view of the similarity of the results described here with those found in MDCK epithelial cells, in which we showed that the Cx43 is a main player [28], it is possible that Cx43 could be involved in the response obtained from some of the cell types tested here.