GJA5 and cancer: Indeed, since the vessels of human tumors express Cx40 (Supplementary Figure S6), a protein which shares large homology with mouse Cx40 in the extra-cellular region which is targeted by 40Gap27 [46], and since loss of Cx40 does not appear to significantly alter the microcirculation established in normal adult tissues, our findings open the challenging perspective that targeting Cx40 may also be useful in the treatment of cancer patients.