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Abstract
Nearly all cancers are caused by abnormalities in the genetic material of the transformed cells. Genetic abnormalities found in cancer typically affect two general classes of genes, cancer promoting oncogenes which are often activated in cancer cells giving those cells new properties such as hyperactive growth and division, protection against programmed cell death, loss of respect for normal tissue boundaries and the ability to become established in diverse tissue environments, tumor suppressor genes are often deactivated in cancer cells resulting in the loss of normal functions in those cells such as accurate DNA replication, control over the cell cycle, orientation and adhesion within tissues and interaction with protective cells of the immune system (fig. 1) (American Cancer Society, 2007).
Genetic abnormalities may be due to the effects of carcinogens such as tobacco smoke, radiation, chemicals and infectious agents. Other cancer-promoting genetic abnormalities may be randomly acquired through errors in DNA replication or are inherited and thus present in all cells from birth. Complex interactions between carcinogens and the host genome may explain why only some individuals develop cancer after exposure to a known carcinogen. After a variable latency period during which they are clinically silent, the malignant cells progress to aggressive invasive and metastatic stages with tumor formation and wide spread dissemination throughout the body (Khorshid, 2009).
Brawer et al. (2009) found that the link between body weight and cancer risk is believed to stem from multiple effects on fat and sugar metabolism, immune function, level of hormones (includ¬ing insulin and estradiol) and cell growth.
The management of malignancies in human begins still constitutes a major challenge of contemporary medicine (Widodo et al., 2007). Chemotherapy often causes severe side effects which are in part a consequence of estruction of normal cells (Khorshid and Moshref, 2006). It was revealed that commonly used anticancer approaches cause significant toxicity in body systems and are responsible for harmful side effects (Moshref et al.