CXADR and cancer: However, the primary Ad5 receptor, coxsackie and adenovirus receptor (hCAR), is ubiquitously expressed in all organs of the human body and on erythrocytes.5,6 Physiologically, its expression pattern in organs co-localizes with tight junction marker, zona occludens ZO-1, and is thus restricted to tight junctions.7 Furthermore, there is increasing evidence suggesting that expression of hCAR correlates negatively with tumor progression in certain cancers.8–10