ABSTRACT
The study of cancer has long been a part of clinical med icine: theories have moved from divine intervention and are now firmly based on the molecular origins of cancer. Cancer cells are able to proliferate in an uncontrolled fashion; their ability to divide and spread is unbounded. Cancer cell growth destroys first the tissue from which they arise and eventually the person in which they are present. Oncogenes are genes with the potential to cause cancer if mutated and expressed at high levels; they are key factors in carcinogenesis. Most oncogenes are normally involved in physiological processes, i.e. cell growth, but if mutated they can predispose a cell to cancer and in concert with other oncogenes can enable cancer cell survival and development of an established tumour. Cancer can spread as individual cells or cell clumps that migrate and implant.
