Although GPIIb-IIIa expression was reported in some malignant cell lines [40, 41], we excluded any potential contribution from non-platelet expressed GPIIb-IIIa: (1) neither M21 nor B16-D5 melanoma cells used in this study express GPIIb-IIIa and (2) the in vivo defect in melanoma cell aggregation and pulmonary retention in GPIIb-/- mice could be rescued by infusion of wildtype platelets. The gene discussed is ITGA2B; the disease is melanoma.