**1. Introduction**

Malignancy is associated with derangement of the dynamic homeostasis of hemostatic system. Associated perturbations are characterized by various clinical manifestations with some of them infrequently being indicative of an occult cancer. The interaction between the presence of hemostatic imbalance and cancer has long been recognized. Starting first with the clinical observations by the French surgeon Armand Trousseau of increased thrombotic tendency in patients with advanced gastric cancer knowledge of the interrelationship between malignan‐ cy and hemostasis has since evolved conceptually into understanding its intrinsic biology. Relationship between hemostasis and cancer is bidirectional. On the one side, it is viewed as a process where the innate defense system of hemostasis modulates cancerous develop‐ ment. On the other side, tumor itself manipulates hemostatic system via paracrine regulato‐ ry mechanisms and utilizes hemostatic functions to induce host tolerance for its development and evasion of immune surveillance. Knowledge of the molecular and cellular processes involved in thrombosis in cancer and their differentiation from the physiological hemostasis is essential for understanding the factors driving the increased tumor-associated prothrom‐ botic tendency. It also allows for identifying the certain hemostatic components as determi‐ nants of the neoplastic process and their incorporation into development of antitumor strategies.
