CLDN2 and lung adenocarcinoma: Some results about Claudin-2, which is expressed markedly in lung adenocarcinoma tissues and A-549 cells, indicated that quercetin could reduce mRNA and protein expression of Claudin-2 in A-549 cell lines without involving Akt and ERK1/2, whereas, Claudin-2 was declined by quercetin mediated by enhancement of miR-16, which is down-regulated in NSCLC, significantly (101).