NUR 1211C Chapter Notes - Chapter Test 4: Tumor Suppressor Gene, Contact Inhibition, Oncogene
8 Feb 2020
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Cancer is a group of diseases characterized by uncontrolled and unregulated growth of cells. Biology of cancer: defect in cell proliferation, most tissues contain a population of undifferentiated cells known as stem cells. Cell proliferation also occurs if the body has a physiologic need for more cells: contact inhibition is that normal cells respect the boundaries and territory of the cells surrounding them. They will not invade a territory that is not their own: cancer cells grown in tissue culture are characterized by loss of contact inhibition. The difference is that proliferation of the cancer cells is indiscriminate and continuous. Sometimes they produce more than two cells at the same time of mitosis (pyramid effect). The time required for a tumor mass to double in size is known as its doubling time: genetic link, protooncogenes are normal cell genes that are important regulators of normal cell processes. Protooncogenes promote growth, whereas tumor suppressor genes suppress growth.
