Anticoagulation, ferrotoxicity and the future of translational lung cancer research.

Numerous studies have shown that elements of coagulation reactions mediate tumor cell proliferation, motility (invasiveness), tissue remodeling and metastasis. Coagulation activation is virtually a universal feature of human malignancy that differs from the clotting response to injury in that it is self-perpetuating rather than self-attenuating. Coagulation activation participates in tumor matrix deposition and local inflammation, and predicts subsequent cancer risk and adverse cancer outcomes. Several clinical trials of anticoagulants have shown improved outcomes in small cell carcinoma of the lung (SCCL) that have been correlated with assembly on the tumor cells of an intact coagulation pathway. However, variable efficacy of anticoagulant therapy has raised doubts about the coagulation hypothesis. Recently, initiators of coagulation and fibrinolytic pathways have been identified that mediate tumor inception and progression. Notable among these is oxidative stress driven by iron-catalyzed reactive oxygen species that may be the basis for local coagulation activation, tumor matrix deposition, inflammation and aberrant properties characteristic of the malignant phenotype. Recognition of important biological characteristics of individual tumor types, disease stage, choice of standard therapy including chemotherapy and the iron status of the host may clarify mechanisms. All of these are subject to modification based on controlled clinical trial design. Further tests of the coagulation hypothesis may lead to novel, low cost and relatively non-toxic approaches to treatment of malignancy including lung cancer that contrast with certain current cancer treatment paradigms.