Role of angiogenetic markers to predict neck node metastasis in head and neck cancers.

Angiogenesis plays a key role in the initiation of growth and metastatic process in cancers. The angiogenic switch may be one of the earliest events in conferring a metastatic potential to the tumor. Further evolution in this multi-step cascade is controlled by the positive and negative regulators of angiogenesis. Recent advances in molecular biology have given a better insight into the mechanisms governing head neck cancer with promising data elaborating the role of angiogenesis. Metastasis to neck nodes is a very important determinant of prognosis, and is more frequently encountered than distant metastasis in head and neck cancers. Systematic PUBMED search of English-language literature of studies involving humans between 1990 and 2008 using the Mesh terms 'pathologic neovascularization', 'head and neck neoplasms', 'lymphatic metastasis' was performed. Quality assessment of selected studies included clinical pertinence, publication in peer reviewed journals, adequate number of enrolled patients. The present article reviews the utility value of various angiogenic parameters and markers that have been utilized to predict regional metastasis including micro vessel density, positive and negative regulators of angiogenesis, and genetic markers for angiogenesis. Although there seems promising preclinical and clinical evidence paving way for novel diagnostic and therapeutic interventions, the implicit role of angiogenesis in metastatic head and neck cancers needs further substantiation.