Abstract:
Aside from their key protective roles in hemostasis and innate immunity, platelets are now
recognized as having multifaceted, adverse roles in the pathogenesis, progression and outcome of
many types of human malignancy. The most consistent and compelling evidence in this context has
been derived from the notable association of elevated circulating platelet counts with the onset and
prognosis of various human malignancies, particularly lung cancer, which represents the primary
focus of the current review. Key topics include an overview of the association of lung cancer with
the circulating platelet count, as well as the mechanisms of platelet-mediated, pro-tumorigenic
immunosuppression, particularly the role of transforming growth factor beta 1. These issues are
followed by a discussion regarding the pro-tumorigenic role of platelet-derived microparticles
(PMPs), the most abundant type of microparticles (MPs) in human blood. In this context, the
presence of increased levels of PMPs in the blood of lung cancer patients has been associated with
tumor growth, invasion, angiogenesis and metastasis, which correlate with disease progression and
decreased survival times. The final section of the review addresses, firstly, the role of cancer-related
platelet activation and thrombosis in the pathogenesis of secondary cardiovascular disorders and the
associated mortality, particularly in lung cancer, which is second only to disease progression; secondly,
the review addresses the potential role of antiplatelet agents in the adjunctive therapy of cancer.