Given that Cx31 expression is similar in HS578T GJB3WT and HCC1143 GJB3Low cells (Fig. 3c), and that neither activate cAMP signaling (Fig. 3h), it is possible that a Cx31 expression threshold is required for breast cancer cells to activate cAMP signaling in adjacent adipocytes. Here, GJB3 is linked to breast carcinoma.