GJA1 and invasive ductal breast carcinoma: Additionally, RT-qPCR validation in 2D cultures of the risk-progression series, using RNU6B as an endogenous control, showed that miR-183-5p was significantly up-regulated by 2.5 folds in Cx43-KO-S1 cells and further up-regulated by 3.5 folds in the invasive ductal carcinoma T4-2 cells34 as compared to their non-neoplastic counterpart, the S1 cells (Fig. 1f).