Smart Nanocarriers Bearing Docetaxel for Improved Chemotherapy Cancer

Cancer is a term used for a collection of diseases in which some of the normal and somatic body cells start dividing and re-dividing out of control . It is a leading cause of the morbidity and mortality worldwide, second only to the cardiovascular diseases . The occurrence of cancer is not new to human kind and the world's oldest recorded case of breast cancer dates back to 1500 BC from ancient Egypt. Some evidences of human osteosarcoma were also found in mummies in ancient Egypt which have been recorded in the manuscripts dated about 1600 B.C . The word cancer, however, was first used by a physician Hippocrates which finds its origin in a Greek word 'karkinos' to describe carcinoma tumors . Our body is made up of the trillions of cells and any one of them could be the site of cancer initiation. During the normal physiological course, the human cells grow and divide to form new cells as and when the need arises (McDonald, Fielding, & Dedhar, 2008). Simultaneously, the old and damaged cells die and new cells replace them. This process operates in a checked manner. But this methodical operation breaks down when cancer develops and cells grow in an unchecked manner. These abnormal cells then form solid growths called tumors . Some cancers like that of blood cells and known as leukemias do not form solid tumors and remain floating in the blood stream and may reach other distal organs. The DNA damage repair, which is an inherent mechanism in normal cells, is compromised in cancerous cells. This damaged DNA can often be inherited leadingto a genetic predisposition to cancer. Cancer can be classified according to the organ of origin or according to the cells of the origin of cancer . On the basis of the cells of origin, major types of clinically identified cancer are carcinomas, sarcomas, leukaemias, lymphomas, myelomas, and brain and spinal cord cancer. Carcinomas are the most common type of cancer begins in the skin or in epithelial cells which lines the external body surface and covers the internal organs. These have been further classified into the subtypes such as, transitional cell carcinoma, basal cell carcinoma, squamous cell carcinoma and adenocarcinoma etc. depending upon the epithelial layer of origin .