Cell biology of cancer

In the cell cycle, dividing cells undergo one mitosis (M) after another, passing through Gi, S (DNA synthesis phase), and G2 phases. Some cells leave the cycle temporarily, entering a Go state from which they can be rescued by appropriate mitogenic stimuli. Other cells leave the cycle permanently, entering terminal differentiation. 

8 Strategies for Specific Drug Targeting to Tumour Cells 

Cancer is a multi-step process in which multiple genetic alterations must occur, usually over a span of years, to have a cumulative effect on the control of cell differentiation, cell division, and growth [3]. 

As in cancer predisposing syndromes, these genetic alterations are sometimes carried in the germline. Among human tumours, heritable mutations are an exception. Most alterations are acquired in somatic life in the form of chromosomal translocations, deletions, inversions, amplifications or point mutations. Certain oncogenic viruses play important roles in a few human tumours. Examples are human papilloma-virus in cervical cancer and skin tumours, Ep-stein-Barr virus in nasopharyngeal carcinoma and Burkitt s lymphoma, and human T-cell leukaemia viruses (e.g. HTLV-I, HTLV-II) in T-cell leukaemia. 

The normally functioning cellular counterparts of the oncogenes, called protooncogenes are also important regulators of biological processes. They are localized in different cell compartments, are expressed at different stages of the cell cycle, and appear to be involved in the cascade of events that maintain the ordered procession through the cell cycle. 

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L2. Liotta, L. A., Principles of molecular cell biology of cancer Cancer metastasis. In Cancer Principles and Practice of Oncology (V. DeVita, Jr., S. Heilman, S. Rosenberg, eds.), 4th ed., pp. 134-149. Lippincott, Philadelphia, 1993. 

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