الفهرس 
Review of literatureOnly 14 pages are availabe for public view
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Abstract
Cancer remains the major devastating disease throughout the world. It is estimated that cancers are responsible for over 6 million lives per year worldwide with an annual 10 million or more new cases. In developing countries, cancers are the second most common cause of death, which comprise 23–25% of total mortality. Despite advances in diagnostic imaging technologies, surgical management, and therapeutic modalities, the long-term survival is poor in most cancers. For example, the five-year survival rate is only 14% in lung cancer and 4% in pancreatic cancer. Cancer biomarkers provide diagnostic, prognostic and therapeutic information about a particular cancer and show their ever-increasing importance in early detection and diagnosis of cancer. Circulating tumor cells (CTCs), also known as the leukemic phase of solid tumors, constitute the hematogenous route of metastasis and most clinical importance for the establishment of distant metastasis during the metastasis of cancer . Disseminated malignancy is responsible for the vast majority of cancer related deaths. During this process, circulating tumor cells (CTC) are generated, spread from the primary tumor, colonize distant organs and lead to overt metstatic disease. CTC are essential for establishing metastasis; however, they are not sufficient as this process is highly inefficient and most will fail to grow in target sites. Several CTC die during migration while others remain dormant for several years and very few grow into macro metastases.