As B7-1 is believed critical to the genesis and progression of tumor disorders, these findings (i) further document the various pathways and mechanisms by which TGF-β can regulate cell proliferation; and, most importantly, (ii) are consistent with the possibility that B7-1 inhibition might reflect a novel and effective means to impact both intrinsic and extrinsic aspects of pancreatic cancer. Here, CD80 is linked to neoplasm.