Malignancy is one of the risk factors of VTE, and VTE is one of the leading causes of death in patients with malignancy [32-34]. The prevalence of VTE in patients with malignancy is 4-7 times higher than that of patients without malignancy [35, 36].

Malignancy results when cancer cells cannot be effectively and timely cleared by the immune system. The author of a recent study [14] reported that necrosis,granulation tissues, disruption of small veins, and dark brown fibrinogens in veins formed mesh-like structure in sigmoid colon adenocarcinoma. Also, a necrotic region in poorly differentiated gastric carcinoma presented with exudation of a large number of red blood cells. Venous thrombosis and hemorrhage serve as inevitable products in the proliferation of cancer cells and disruption of the surrounding veins and arteries.