Paxillin is a signal transduction adaptor protein that is expressed at focal adhesions of non-striated cells and at costameres of striated muscle cells. It functions to adhere cells to the extracellular matrix. Mutations as well as abnormal expression of paxillin protein has been implicated in the progression of various cancers. Enhanced expression of paxillin has been detected in premalignant areas of hyperplasia, squamous metaplasia and goblet cell metaplasia, as well as dysplastic lesions and carcinoma in high-risk patients with lung adenocarcinoma. Mutations have been associated with enhanced tumor growth, cell proliferation, and invasion in lung cancer tissues.