Cancer is a disease caused by normal cells changing so that they grow in an uncontrolled way. The uncontrolled growth causes a lump called a tumour to form. There are over 200 different types of cancer because there are over 200 different types of body cells. For example, cells that make up the lungs can cause a lung cancer. This review highlights the Hallmarks of Cancer, with Apoptosis and Metastasis & tissue invasion coming under particular scrutiny. Apoptosis has a crucial role to play in maintenance of bodily health and is one of the many areas currently being examined in order to develop new cancer treatments. Although the determinants of Metastasis are not completely understood there are several theories being developed in order to gain further insight and develop new drugs to suppress the process for example, the alterations of CAMs. The p53 protein is crucial in multicellular organisms, where it regulates the cell cycle and, thus, functions as a tumor suppressor. The p53 protein is highlighted in this review in terms of its role in the cell cycle and also in terms of its contribution to apoptosis and apoptosis evasion. Carcinogenic agents and their role in DNA sequence mutations are outlined, as are cellular mechanisms such as photo-reactivation that play a pivotal part in the regulation of mutated DNA sequences. .
The term 'Cancer' stems from the Latin term for 'crab'. (Stephens 1997) explains that cancer derived from this meaning because, in ancient times, advanced cancer was thought to resemble a crab's claws reaching out from one cell into surrounding tissue. (King 1996) clinically defines cancer as: 'A set of diseases characterised by unregulated cell growth leading to invasion of surrounding tissues and spread to other parts of the body'. This statement is a general outline used in order to convey an understanding of the topic. Some characteristics of a cancer cell, as outlined by (Hanahan & Weinberg 2000) are: Evading apoptosis, Self-sufficiency in growth signals, Insensitivity to anti-growth signals, sustained angiogenesis, Limitless replicative potential and Tissue invasion & Metastasis.