International Medical Journal Vol. 23, No. 5, pp. 490 - 493 , October 2016 CANCER Angiogenesis in Tumor Growth: A Review Arpita Kabiraj 1) , Tanya Khaitan 1) , Preeti Tomar Bhattacharya 1) , Jagriti Gupta 2) , Shan Nawaz Malik 3) , Mohammad Khursheed Alam 4) ABSTRACT Background: Oral squamous cell carcinoma (OSCC) is a malignant neoplasm arising from the dysplastic epithelium of the oral cavity. It arises as a result of multiple molecular events that develop from the combined influences of an individual's genetic predisposition and exposure to environmental carcinogens. As OSCCs grow, invade and metastasize, new blood vessel formation is critical. OSCCs, like most tumors, are able to create a blood supply by stimulating endothelial cell proliferation and new blood vessel formation. Review summary: Angiogenesis, the growth of new blood vessels from pre-existing ones, is one of the essential phenotypes of tumor formation and it typically involves sprouting, branching and differential growth of pre-existing blood vessels, as well as the recruitment of supporting cells associated with the endothelium, including smooth muscle cells and pericytes. Tumor angio- genesis and the density of newly formed vessels are of potential prognostic relevance in the assessment of malignant neoplasia. Conclusion: Although the results of some clinical trials have been disappointing, a better understanding of the correct timing for the use of antiangiogenic drugs, the selection of patients that can really benefit from these treatments and the combination with cooperating conventional therapies will very likely place these agents among the most advanced anticancer strategies. KEY WORDS oral squamous cell carcinoma, angiogenesis, carcinogenesis, angiogenic factors, endothelial cells Received on February 17, 2015 and accepted on February 3, 2016 1) Haldia Institute of Dental Sciences and Research Purba Medinipur, Haldia West Bengal, India 2) Sardar Patel Post Graduate Institute of Dental & Medical Sciences Lucknow, U.P, India 3) Yenepoya Dental College Mangalore, India 4) School of Dental Sciences, Health Campus, Universiti Sains Malaysia Correspondence to: Arpita Kabiraj (e-mail: arpita.kabiraj82@gmail.com) 490 INTRODUCTION Cancer is a multifactorial disease brought on by a combination of causal and predisposing genetic factors and which at a given moment and under favourable conditions may take effect in predisposed people. Mortality from malignant neoplasm figures among the principle causes of death worldwide and it is therefore, a highly serious public health matter 1) . Cancer is increasingly recognized to be a global problem and not one limited to the industrial nations. At present there is a great varia- tion in the patterns of cancer occurrence in different regions of the world 2) . The term 'oral cancer' includes a diverse group of tumors character- ized by proliferative lesions and tumor like masses arising from the oral tissue. It is the sixth most common cancer in the world accounting for approximately 4% of new cancer cases and 2% of all cancer deaths worldwide 3,4) . The world epidemiology registers over 300,000 new cases of oral cancer annually 1) . According to World Health Organization (WHO), carcinoma of oral cavity in males in developing countries, is the sixth commonest cancer after lung, prostrate, colorectal, stomach and bladder cancer, while in females, it is the tenth commonest site of cancer after breast, colorectal, lung, stomach, uterus, cervix, ovary, bladder and liver 5) . More than 95% of the carcinomas of the oral cavity are squamous cell type, in nature. They constitute a major health problem in develop- ing countries, representing a leading cause of death. The survival index continues to be small (50%), as compared to the progress in diagnosis and treatment of other malignant tumors 5) . Squamous cell carcinoma is defined as "A malignant epithelial neoplasm exhibiting squamous differ- entiation as characterized by the formation of keratin and/or the pres- ence of intercellular bridges" (Pindborg JJ et al. 1997) 6) . The World Health Organization (WHO) reported oral cancer as having one of the highest mortality ratios amongst all malignancies 4) . WHO expects a worldwide rising oral squamous cell carcinomas (OSCC) incidence in the next decades 7) . Oral cancer incidence and mortality rates vary widely across the world, and the highest rates are generally registered in a few developing countries including India, Pakistan and Bangladesh, where this is the most common form of cancer and also in Hong Kong, Singapore and the Philippines. Also, within Europe, there is a wide variability in oral cancer rates and appreciable differences among areas of the same coun- try 8) . The etiology and risk factors of oral cancer is multifactorial. Genetic, environmental, social and behavioural effects may all be impli- cated 4) . Tobacco and alcohols are the two most important known risk factors for the development or oral cancer. Cofactors in OSCC include dietary factors, immunodeficiency and viral infections like HPV 16/18 5) . OSCC arises as a result of multiple molecular events that develop from the combined influences of an individual's genetic predisposition and exposure to environmental carcinogens 9) . The changes include the aberrant expression and function of molecules regulating cell signalling, growth, survival, motility, angiogenesis and cell cycle control 10) . As OSCCs grow, invade and metastasize, new blood vessel formation is critical. OSCCs, like most tumors, are able to create a blood supply by stimulating endothelial cell proliferation and new blood vessel forma- C 2016 Japan Health Sciences University & Japan International Cultural Exchange Foundation