In one striking example, pyocyanin from Pseudomonas aeuroginosa (PA) upregulates SLex on mucins expressed by the bronchial epithelium to allow the bacterium to adhere and invade.39 However, although both cancer and inflammation are associated with abnormal mucin glycosylation, what is much less clear is whether there are physiological selectin ligands expressed on mucins in the healthy lung that play a role in normal lung homeostasis. This evidence concerns the gene MUC5AC and cancer.