PTGS2 and Pleural effusion: The pioneering investigation of gene expression profiles in brain-seeking derivatives of two lines originally derived from TNBC pleural effusions (MDA-MB-231 and CN34) identified that COX2, HBEGF, and ST6GALNAC5 are enhancers of BBB extravasation [89]; COX2 and HBEGF, but not ST6GALNAC5, also likely function in extravasation in the lung.