الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Cancer is a major public health problem worldwide. It is the second leading cause of death in the United States, and is expected to exceed heart diseases as the leading cause of death in the next few years (Siegel et al., 2014). The word cancer came from a Greek word karkinos to define carcinoma tumors by a physician Hippocrates (460–370 B.C), but Hippocrates was not the first to discover this disease. Some of the earliest evidence of human bone cancer was found in mummies in ancientEgypt and in ancient manuscripts dates about 1600 B.C. The world’s oldest recorded case of breast cancer hails from ancient Egypt in 1500 B. C. and it was recorded that there was no treatment for the cancer, only palliative treatment. According to inscriptions, surface tumors were surgically removed in a similar manner as they are removed today(Sudhakar 2009).
Chemical carcinogenesis is a major cause of malignant neoplasm, and polycyclic aromatic hydrocarbons (PAHs) are major chemical carcinogens contained in cigarette smoke, burnt foods and exhaust fumes of vehicles(Taguchi et al., 2006). 7,12-dimethylebenz (a) anthracene (DMBA) is a potent carcinogenic polycyclic aromatic hydrocarbon (PAH) used to cause induction of mammary cancers in animal models and is well known as cytotoxic, carcinogenic, mutagenic and immunosuppressive agent(Lindhe et al., 2002; Buters et al., 2003). Al-Attar (1998) reported that DMBA induced hematological and hematochemical parameters changes in toad (Bufo regularis) as well as DMBA induced hepatocellular carcinoma(Al-Attar 1998). Also, DMBA induced hepatic neoplasms in the Egyptian toad Bufo regularis(Sadek 1986) and Bufo viridis(Sadek and Abdul-Salam 1994b). It is documented that similarities in cytological characteristics between tumors in toad and humans (Abdelmeguid et al., 1997). Experimental studies showed that induction of skin, oral, mammary and ovarian tumors in rats(Han et al., 2002) , mice (Buters et al., 2003), and hamsters (Li et al., 2002b) was caused by DMBA.
Cancer treatment is very much dependent on the method of delivery. In the past, various anticancer drugs were used by cancer patients. The role of drugs such as vitamins and non-steroidal anti-inflammatory agents in the presentation of neoplasms is becoming increasingly obvious. Vitamin A has been shown to inhibit the development of chemically induced tumors in hamsters (Wenger et al., 2001), mouse(Albright et al., 2004), rat (Tachibana et al., 1984) and toad (Sadek 1981; Sadek and Hayat 1996). Studies showed that toads have been used as a model to assay the development of tumors in relation to carcinogenic(Sadek 1984) , co-carcinogens (Sadek and Abdul-Salam 1994b), and vitamins (Sadek and Abdelmegid 1982).These drugs were less successful and had major side effects.
Scientists’ attention had been attracted to nanoparticles because of their multifunctional character. Cancer treatment using nanoparticles is the latest achievement in the medical field(Pathak and Katiyar 2007). Feynman in 1959 was the first to provide the basis for the concept of nanotechnology. While Taniguchi in 1974 is the one who created the word Nanotechology. Nanotechnology is the molecular structures that is in the range of 1 to 100 nanometer (Alivisatos 1996; Sutherland 2002; Parida and Das 2008). One nanometer (1nm) is one billionth or 107 of a meter or 1/80,000 the width of a human hair or about combined diameter of 10 hydrogen atoms. To refer some examples: most human cells are 10,000 to 20,000 nm & most viruses are 10 to 100nm and Hemoglobin molecule is 5nm (Parida and Das 2008).
Nanotechnology is a multidisciplinary field that uses principles from chemistry, biology, physics, and engineering to design and fabricate nanoscale devices (Fox 2000; Peppas 2004; Ferrari 2005; Sinha et al., 2006; Uchegbu 2006; Jiang et al., 2007; Farokhzad and Langer 2009). In its strictest definition, nanotechnology refers to structures with a size range of 1–100 nm in at least one dimension (Alexis et al., 2010).
2. REVIEW OF LITERATURE
2.1. Cancer
Cancer is a leading cause of death in both developed and developing countries; the burden is expected to grow worldwide due to the growth and aging of the population, particularly in less developed countries, in which about 82% of the world’s population. The adoption of lifestyle behavior that are known to increase cancer risk, such as smoking, poor diet, physical inactivity, and reproductive changes (including lower parity and later age at first birth), have further increased the cancer burden in less economically developed countries(Torre et al., 2015).
Cancer develops when normal cells in a particular part of the body begin to grow out of control. There are different types of cancers; all types of cancer cells continue to grow, divide and re-divide instead of dying and form new abnormal cells. Some types of cancer cells often travel to other parts of the body through blood circulation or lymph vessels (metastasis), where they begin to grow. Generally cancer cells develop from normal cells due to damage of DNA. Most of the time when ever DNA was damaged, the body is able to repair it, unfortunately in cancer cells, damaged DNA is not repaired. People can also inherit damaged DNA from parents, which accounts for inherited cancers. Many times though, a person’s DNA becomes damaged by exposure to something in the environment, like smoking (Sudhakar 2009).
Global action is needed to stem the increasing burden of non-communicable diseases, especially in low-income and middle-income countries which now bear 80% of the worldwide burden of such diseases. The UN has forecast that the global population will reach 7 billion by 2012 and 8•3 billion by 2030. The effect of population ageing and growth will be greatest in low-income and middle-income countries. These changes translate to a predicted global burden of 20.3 million new cancer cases by 2030 compared with an estimated 12.7 million cases in 2008, and a predicted 13.2 million cancer-related deaths worldwide by 2030, up from 7.6 million in 2008 (Bray et al., 2012). While incidence rates for all cancers combined in economically developed countries are nearly twice as high as in economically developing countries in both males and females, mortality rates for all cancers combined in developed countries are only 21% higher in males and only 2% higher in females(Jemal et al., 2011).
Cancer Registries in North Africa (Morocco, Algeria, Tunisia, Libya, Egypt) increased in number from one to nine, and covered 13% of the total regional population. The total cancer burden in North Africa countries was between one third and one half of what was observed in Europe. The overall incidence rate in men (world age standardized, per 100,000) ranges from 86.3 in Setif, Algeria, to 156.1 in Gharbiah, Egypt. The range is similar in women: from 80.3 in Setif to 164.0 in Algier, both Algeria. The case mix and the level of rates are quite homogeneous in the countries considered(Zanetti et al., 2010).
Despite prodigious advances in our understanding of the disease, cancer remains one of the leading causes of death in the United States. More than 1.5 million new cases of cancer were projected for 2010, with an anticipated mortality rate of 37%(Bardhan et al., 2011).
Conventional chemotherapeutic agents are distributed nonspecifically in the body where they affect both cancerous and normal cells, thereby limiting the dose achievable within the tumor and also resulting in suboptimal treatment due to excessive toxicities(Cho et al., 2008). In chemotherapy, clinical drug resistance may be defined either as a lack of tumor size reduction or as the occurrence of clinical relapse after an initial positive response to anti-tumor treatment (Brown and Links 1999).First, non-cellular drug resistance mechanisms could be due to poorly vascularized tumor regions which can effectively reduce drug access to the tumor and thus protect cancerous cells from cytotoxicity.