A study on pancreatic ductal adenocarcinoma by Solan et al. confirmed that GJs are abundant in stromal cells of Kras (LSL-G12D/+; p48Cre/+) mice but absent in KC; Cx43 (CK1A) mice (crossing the Cx43(CK1A) mouse onto the KC background), and that KC;Cx (CK1A) cells can efficiently downregulate Cx43 expression [89]. This evidence concerns the gene CALCA and pancreatic ductal adenocarcinoma.