Although bladder cancers are very common, little is known about their molecular pathogenesis. In this study, invasive bladder cancers were evaluated for the presence of gene mutations in the p53 suppressor gene. Of 18 tumors evaluated, 11 (61 percent) were found to have genetic alterations of p53. The alterations included ten point mutations resulting in single amino acid substitutions, and one 24-base pair deletion. In all but one case, the mutations were associated with chromosome 17p allelic deletions, leaving the cells with only mutant forms of the p53 gene products. Through the use of the polymerase chain reaction and oligomer-specific hybridization, p53 mutations were identified in 1 to 7 percent of the cells within the urine sediment of each of three patients tested. The p53 mutations are the first genetic alterations demonstrated to occur in a high proportion of primary invasive bladder cancers. Detection of such mutations ex vivo has clinical implications for monitoring individuals whose tumor cells are shed extracorporeally.
A number of bladder tumors can arise from the uncontrolled spread of a single transformed cell. These tumors can then grow independently with variable subsequent genetic alterations.
In 1997, based on revised projections, prostate cancer will be diagnosed in an estimated 209,900 American men; 41,800 will die of the disease, making it the second leading cause of cancer death in men after lung cancer.1 Prostate cancer accounts for 36% of all male cancers in the United States and 13% of cancer-related deaths in men.The incidence of prostate cancer is 66% higher among African-American men than among white men. In fact, African-American men experience the highest prostate cancer incidence rates in the world, and associated mortality rates are twice those of white men. Nineteen percent of all cancer deaths among African-American men are caused by prostate cancer.
2The disease is common in North America and northwestern Europe and is rare in the Near East, Africa, and South America. The familial tendency to develop prostate cancer may be the result of genetic or environmental factors. Some research suggests that dietary fat may also play a role in the development of prostate cancer.
2Between 1988 and 1992, the incidence of prostate cancer in the United States increased dramatically. This increase has been attributed largely to the introduction and widespread application of prostate-specific antigen (PSA) screening. During the same period, a shift occurred to an earlier stage at the time of diagnosis; that is, the number of cases of local and regional disease at diagnosis increased, and the finding of distant disease at diagnosis decreased. Overall 5-year prostate cancer survival rates also increased.No direct evidence exists to date to show that PSA screening decreases prostate cancer mortality rates. Prospective studies are underway to examine this potential link, but so far none has documented any reduction in mortality as a direct result of screening. Indirect evidence, however, suggests that prostate cancer C A C a n c e r J C l i n 1 9 9 7 ; 4 7 : 2 6 1 -2 6 4 Vol. screening has resulted in the diagnosis of earlier-stage disease in more younger men, which could influence mortality.
Update of GuidelineIn 1992, the American Cancer Society issued the following prostate cancer screening recommendation: Men age 50 years and older should undergo digital rectal examination and PSA testing annually. If either is abnormal, further evaluation should be considered. In March 1997, the ACS convened a workshop to review this guideline in light of the expanding body of clinical research data about prostate cancer screening and early detection. Based on compelling intermediate data from ongoing clinical trials suggesting that prostate cancer screening may result in the discovery of more early-stage disease (and therefore a potential increase in the cure rate), the ACS updated the 1992 guideline. The Board of Directors of the ACS approved the following updated guideline on June 10, 1997: The ACS recommends that both the PSA test and the digital rectal examination be offered annually, beginning at age 50, to men who have a life expectancy of at least 10 years and to younger men who are at high risk. Information...
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