Sarcoma spreads primarily through the vascular system: are there biomarkers associated with vascular spread?

Sarcomas are a heterogeneous group of tumors with specific molecular characteristics and currently classified on the basis of their tissue of origin and histologic appearance. Except for epithelioid sarcoma, clear cell sarcoma, angiosarcoma and rhabdomyosarcoma, which may spread to regional lymph nodes, the other histotypes spread via the vascular system to the lungs most of the time. A variety of molecular approaches, including gene expression profiling, have identified candidate biomarkers and generated insights into sarcoma biology. The comprehension of the pathogenesis of this malignancy according to the mesenchymal stem cell hypothesis parallels the description of several molecular pathways deregulated in sarcoma. Individuation of vascular spread biomarkers is actually focused on the study of factors involved both in hemostasis and angiogenesis. Interestingly the microenvironment of sarcomas showed the very same mesenchymal origin of the surrounding stromal cells. The presence of circulating tumor cells and miRNAs in blood samples of sarcoma patients represents the possibility not only to better stratify patients group according to the prognosis but also to tailor new individualized therapy. So, it could be predicted that some genes expressed in a specific sarcoma might have prognostic significance or therapeutic targeting potential and molecular targets can be identified in the tumor or in the tumor microenvironment. Therefore the initial evaluation of a sarcoma patient should include in-depth genetic evaluation including karyotyping and c-DNA/protein expression profiling. The chemokine signaling demonstrated to be deeply implicated in sarcoma development as well as to have a significant role in development of metastatic disease, especially in directing tumor cells towards the preferential sites of metastases in sarcoma, lung and bone. It is unsolved if the blood stream is a more favorable environment compared to lymphatic or if lymph nodes are more efficient in destroying metastatic sarcoma cells. But the comprehension of the regulatory mechanisms of the behavior of mesenchymal malignant tumors is at its dawn.