BIOC33H3 Lecture Notes - Histology, Cellular Differentiation, Oncogene
25 Mar 2013
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Document Summary
Cancer encompasses a broad range of diseases of multiple causes that can arise in any cell of the body capable of evading regulatory controls over proliferation and differentiation. Two major dysfunctions present in the process of cancer are (1) defective cellular proliferation (growth) and (2) defective cellular differentiation. Cancer cells usually proliferate at the same rate of the normal cells of the tissue from which they arise. However, cancer cells divide indiscriminately and haphazardly and sometimes produce more than two cells at the time of mitosis. Protooncogenes are normal cellular genes that are important regulators of normal cellular processes. When these genes become mutated, they can begin to function as oncogenes (tumor-inducing genes). Tumors can be classified as benign or malignant: benign neoplasms are well-differentiated, malignant neoplasms range from well-differentiated to undifferentiated. Since cancer cells arise from normal human cells, the immune response mounted against cancer cells may be inadequate to effectively eradicate them.
