Similar protooncogenes are associated with human cancers, though these genes are probably not of retrovirus origin. It is likely that the oncogenes stimulating cell proliferation in human cancers were originally protooncogenes that stimulated such useful proliferative processes as those involved in wound healing, hematopoiesis and embryogenesis. A change in the gene sufficient to produce a one amino acid change in the protein product can be induced by a virus, chemical carcinogens damaging cell DNA, and spontaneous chromosome breakage and rearrangement could all transform a protooncogene into an oncogene. Phosphorylation regulates enzyme activity, and oncogene proteins are known to phosphorylate proteins that function in regulation of growth-stimulating substances such as platelet-derived growth factor and epidermal growth factor (Weinberg, 1983).
These cancerous cellular changes may affect the way the whole body functions or cause very localized changes. In cases of colorectal cancer there are a variety of polyposis syndromes ranging from benign hyperplastic polyps that do not go malignant and premalignant sessile vinous adenomas to adenomatous polyps, Gardener's syndrome (polyps unevenly distributed, dental abnormalities, epidermoid cysts, mesenteric or peritoneal fibrosis, keloids, desmoids, osteomas), Peutz-Jegher's syndrome (multiple polyps and deep pigmentation of fingers, mucosa and lips) and Turcot's syndrome (malignant neurologic tumors and colonic polyps). If the polyps are not treated (e.g. by resection), then colonic, rectal and colorectal carcinomas are likely to develop (Freed, 1984).
In the case of a bronchiogenic carcinoma the bodily changes may be reflected in symptoms like malaise, dyspepsia, weight loss and chronic cough with chest x-rays revealing lung opacities, and a biopsy revealing malignancy to the doctor. However, the course of the disease can vary from eventual death of the patient due to worseni...
Effects of Cancer to our Life. (1969, December 31). In LotsofEssays.com. Retrieved 05:41, December 22, 2014, from http://www.collegetermpapers.com/viewpaper/1303810546.html