Naturally Occurring Carcinogens

  • Raymond J. Shamberger


Some toxic chemicals, especially those produced by microbes and plant cells, exhibit carcinogenic activity. Even though some of these compounds are integral components of foods relatively common in the diet of humans, many of these carcinogens have also been found in unusual food sources or in foods contaminated by microorganisms or unwanted plant materials. Sometimes the potential hazards to human health by these components or contaminants of foods range from small to very large. Very low levels of exposure to chemicals with weak carcinogenic activity in laboratory animals may be of little risk to human populations. However, the presence of aflatoxin B1 in foods is a matter of considerable concern, because aflatoxin B1 is a potent carcinogen for a number of species, and epidemiological data suggest that this carcinogen may play a role in the development of cancer in humans living in some parts of Africa and the Far East.1,2


Esophageal Cancer Swiss Mouse Tree Shrew Pyrrolizidine Alkaloid Aflatoxin Contamination 
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  1. 1.
    Peers, F. G., Gilman, G. A., and Linsell, C. A. 1976. Dietary aflatoxins and human liver cancer. A study in Swaziland. Int. J. Cancer 17: 167–176.PubMedCrossRefGoogle Scholar
  2. 2.
    van Rensberg, S. J., van der Watt, J. J., Purchase, I. F. H., Coutinho, L. P., and Markham, R. 1974. Primary liver cancer rate and aflatoxin intake in the high cancer area. South Afr. Med. J. 48: 2508a–2508d.Google Scholar
  3. 3.
    U.S. Food and Drug Administration. 1980. Nuts. in Compliance policy guidelines. Washington, D.C.: Division of Field Regulatory Guidance, Bureau of Foods, Food and Drug Administration.Google Scholar
  4. 4.
    Oettle, A. G. 1965. The aetiology of primary carcinoma of the liver in Africa: A critical appraisal of previous ideas with an outline of the mycotoxin hypothesis. South Afr. Med. J. 39: 917–925.Google Scholar
  5. 5.
    Keen, P., and Martin, P. 1971. The toxicity and fungal infestation of foodstuffs in Swaziland in relation to harvesting and storage. Trop. Geogr. Med. 23: 35–43.PubMedGoogle Scholar
  6. 6.
    Alpert, M. E., Hutt, M. S. R., Wogan, G. N., and Davidson, C. S. 1971. Association between aflatoxin content of food and hepatoma frequency in Uganda. Cancer 28: 253–260.PubMedCrossRefGoogle Scholar
  7. 7.
    Peers, F. G., Gilman, G. A., and Linsel, C. A. 1976. Dietary aflatoxins and human liver cancer. A study in Swaziland. Int. J. Cancer 17: 167–176.PubMedCrossRefGoogle Scholar
  8. 8.
    Peers, F. G., and Linsell, C. A. 1973. Dietary Aflatoxins and liver cancer—A population based in Kenya. Br. J. Cancer 27: 473–484.PubMedCrossRefGoogle Scholar
  9. 9.
    Wogan, G. N. 1975. Dietary factors and special epidemiological situations of liver cancer in Thailand and Africa. Cancer Res. 35: 3499–3502.PubMedGoogle Scholar
  10. 10.
    Armstrong, B. 1980. The epidemiology of cancer in the People’s Republic of China. Int. J. Epidemiol. 9: 305–315.PubMedCrossRefGoogle Scholar
  11. 11.
    Tung, T. C., and Ling, K. H. 1968. Study on aflatoxin of foodstuffs in Taiwan. J. Vitaminol. 14(Suppl.): 48–52.CrossRefGoogle Scholar
  12. 12.
    Linsell, C. A., and Peer, F. G. 1977. Aflatoxin and liver cell cancer. Trans. R. Soc. Trop. Med. Hyg. 71: 471–473.PubMedCrossRefGoogle Scholar
  13. 13.
    Chien, M. C., Tong, M. J., Lo, K. J., Lee, J. K., Milich, D. R., Voyas, G. N., and Murphy, B. L. 1981. Hepatitis B viral markers in patients with primary hepatocellular carcinoma in Taiwan. J. Natl. Cancer Inst. 66: 475–479.PubMedGoogle Scholar
  14. 14.
    Kew, M. C., Desmyter, J. Bradfurne, A. F., and Macnab, G. M. 1979. Hepatitis B virus infection in southern African blocks with hepatocellular cancer. J. Natl. Cancer Inst. 62: 517–520.PubMedGoogle Scholar
  15. 15.
    Yang, C. S. 1980. Research on esophageal cancer in China: A review. Cancer Res. 68: 211–216.Google Scholar
  16. 16.
    Dvorackova, I., Kusak, V., Vesely, D., Vesela, J., and Nesnidal, P. 1977. Aflatoxin and encephalopathy with fatty degeneration of viscera (Reye). Ann. Nutr. Aliment. 31: 977–989.PubMedGoogle Scholar
  17. 17.
    Becroft, D. M. D., and Webster, D. R. 1972. Aflatoxin and Reye’s disease. Br. Med. J. 4: 117.PubMedCrossRefGoogle Scholar
  18. 18.
    Siraj, M. Y., Hayes, A. W., Unger, P. D., Hogan, G. R., Ryan, N. J., and Wray, B. B. 1981. Analysis of Aflatoxin B1 in human tissues with high-pressure liquid chromatography. Toxicol. Appl. Pharmacol. 58: 422–430.PubMedCrossRefGoogle Scholar
  19. 19.
    Wogan, G. N. 1973. Aflatoxin carcinogenesis. in H. Busch (Ed.) Methods in cancer research. Vol. 7. pp. 309–344. New York: Academic Press.Google Scholar
  20. 20.
    Butler, W. H., and Barnes, J. M. 1966. Carcinoma of the glandular stomach in rats given diets containing aflatoxin. Nature 209: 90.PubMedCrossRefGoogle Scholar
  21. 21.
    Newberne, P. M., and Rogers, A. E. 1973. Rat colon carcinomas associated with aflatoxin and marginal vitamin A. J. Natl. Cancer Inst. 50: 439–448.PubMedGoogle Scholar
  22. 22.
    Epstein, S. M., Bartus, B., and Farber, E. 1969. Renal epithelial neoplasms in male Wistar rats by oral aflatoxin B1. Cancer Res. 29: 1045–1050.PubMedGoogle Scholar
  23. 23.
    Newberne, P. M., Hunt, C. E., and Wogan, G. N. 1967. Neoplasms in the rat associated with administration of urethan and aflatoxin. Exp. Mol. Pathol. 6: 285–299.PubMedCrossRefGoogle Scholar
  24. 24.
    Vesselinovitch, S. D., Mihailovich, N., Wogan, G. N., Lombard, L. S., and Rao, K. V. N. 1972. Aflatoxin B1, a hepatocarcinogen in the infant mouse. Cancer Res. 32: 2289–2291.PubMedGoogle Scholar
  25. 25.
    Stoloff, L., and Friedman, L. 1976. Information bearing on the evaluation of the hazard to man from aflatoxin ingestion. PAG Bull. 6: 21–32.Google Scholar
  26. 26.
    Adamson, R. H., Correa, P., and Dalgard, D. W. 1973. Occurrence of a primary liver carcinoma in a rhesus monkey fed aflatoxin B1. J. Natl. Cancer Inst. 50: 549–553.PubMedGoogle Scholar
  27. 27.
    Lin, J. J., Liu, C., and Svoboda, D. J. 1974. Long-term effects of aflatoxin B1 and viral hepatitis on marmoset liver. Lab. Invest. 30: 267–278.PubMedGoogle Scholar
  28. 28.
    Reddy, J. K., Svoboda, D. J., and Rao, M. S. 1976. Induction of liver tumors by aflatoxin B1 in the tree shrews (tupaiaglis), a non-human primate. Cancer Res. 36: 151–160.PubMedGoogle Scholar
  29. 29.
    Ueno, Y., Kubota, K., Ito, T., and Nakamura, Y. 1978. Mutagenicity of carcinogenic mycotoxins in Salmonella typhimurium. Cancer Res. 38: 536–542.PubMedGoogle Scholar
  30. 30.
    Ueno, Y., and Kubota, K. 1976. DNA-attacking ability of carcinogenic mycotoxins in recombination-deficient mutant cells of Bacillus subtilis. Cancer Res. 36: 445–451.PubMedGoogle Scholar
  31. 31.
    Umeda, M., Tsutsui, T., and Saito, M. 1977. Mutagenicity and inducibility of DNA single-strand breaks and chromosome aberrations by various mycotoxins. Gann 68: 619–625.PubMedGoogle Scholar
  32. 32.
    Wong, J. J., and Hsieh, D. P. H. 1976. Mutagenicity of aflatoxins related to their metabolism and carcinogenic potential. Proc. Natl. Acad. Sci. (USA) 73: 2241–2244.CrossRefGoogle Scholar
  33. 33.
    Kanisawa, M., and Suzuki, S. 1978. Induction of renal and hepatic tumors in mice by ochratoxin A, a mycotoxin. Gann 69: 599–600.PubMedGoogle Scholar
  34. 34.
    Wehner, F. C., Thiel, P. G., van Rensburg, S. J., and Demasius, I. P. C. 1978. Mutagenicity to Salmonella typhimurium of some Aspergillus and Penicillium mycotoxins. Mutat. Res. 58: 193–203.PubMedCrossRefGoogle Scholar
  35. 35.
    Schoental, R., Joffe, A. Z., and Yagen, B. 1979. Cardiovascular lesions and various tumors found in rats given T-2 toxin, a trichothecene metabolite of Fusarium. Cancer Res. 39: 2179–2189.PubMedGoogle Scholar
  36. 36.
    Dickens, F., and Jones, H. E. H. 1965. Further studies on the carcinogenic action of certain lactones and related substances in the rat and mouse. Br. J. Cancer 19: 392–403.PubMedCrossRefGoogle Scholar
  37. 37.
    Becci, P. J., Hess, F. G., Johnson, W. D., Gallo, M. A., Babish, J. G., Cox, G. E., Daily, R. E., and Parent, R. A. 1981. Long-term carcinogenicity and toxicology studies of patulin in the rat. J. Appl. Toxicol. 1: 256–261.PubMedCrossRefGoogle Scholar
  38. 38.
    Umeda, M., Yamamoto, T., and Saito, M. 1972. DNA-strand breakage of Hela cells induced by several mycotoxins. Jpn. J. Exp. Med. 42: 527–537.PubMedGoogle Scholar
  39. 39.
    International Agency for Research on Cancer. 1976. LARC monographs on the evolution of the carcinogenic risk of chemicals in man. Vol. 10: Some naturally occurring substances. Lyons, France:International Agency for Research on Cancer.Google Scholar
  40. 40.
    Stark, A. A., Townsend, J. M., Wogan, G. N., Demain, A. L., Manmade, A., and Ghosh, A. C. 1978. Mutagenicity and antibacterial activity of mycotoxins produced by Penicillium is-landicum Sopp and Penicillium regulosum. J. Environ. Pathol. Toxicol. 2: 313–324.PubMedGoogle Scholar
  41. 41.
    Miller, J. A. 1973. Naturally occurring substances that can induce tumors. in Toxicants occurring naturally in foods. 2nd ed. pp. 508–549. Washington, D.C.: Food and Nutrition Board, National Academy of Sciences.Google Scholar
  42. 42.
    Nelson, A. A., Fitzhugh, O. G., Morris, H. J., and Calvery, H. O. Neurofibromas of rat ears produced by prolonged feeding of crude ergot. Cancer Res. 2: 11–15.Google Scholar
  43. 43.
    Toth, B., Nagel, D., Patil, K., Erickson, J., and Antonson, K. 1978. Tumor induction with the N′-acetyl derivative of 4-hydroxymethylphenylhydrazine, a metabolite of agaritine of Agaricus bisporus.Google Scholar
  44. 44.
    Levenberg, B. 1962. An aromatic diazoneium compound in the mushroom Agaricus bisporus. Biochim. Biophys. Acta 63: 212–214.PubMedCrossRefGoogle Scholar
  45. 45.
    Levenberg, B. 1964. Isolation and structure of agaritine, a glutamylsubstituted arylhydrazine derivative from Agaricaceae. J. Biol. Chem. 239: 2267–2273.PubMedGoogle Scholar
  46. 46.
    Toth, B., Smith, J., and Patil, K. 1981. Cancer incidence in mice with acetaldehyde methylfor-mylhydrazone of the false morel mushroom. J. Natl. Cancer Inst. 67: 881–887.PubMedGoogle Scholar
  47. 47.
    Toth, B., Tompa, A., and Patil, K. 1977. Tumorigenic effect of 4-methylphenylhydrazine hydrochloride in Swiss mice. Z. Krebsforsch. Klin. Onkol. 89: 245–252.CrossRefGoogle Scholar
  48. 48.
    Rogan, E. G., Walker, B. A., Gingell, R., Nagel, D., and Toth, B. 1982. Microbial mutagenicity of selected hydrazines. Mutat Res. 102: 447–455.CrossRefGoogle Scholar
  49. 49.
    Shimizu, H., Hayashi, K., and Takemura, N. 1978. Relationships between the mutagenic and carcinogenic effects of hydrazine derivatives. Nippon Eiseigaku Zasshi 33: 474–485.PubMedCrossRefGoogle Scholar
  50. 50.
    Toth, B., and Patil, K. 1981. Cyromitrin as a tumor inducer. Neoplasma 28: 559–564.PubMedGoogle Scholar
  51. 51.
    Toth, B., and Patil, K. 1979. Carcinogenic effects in the Syrian golden hamster of N-methyl-N-formylhydrazine of the false morel mushroom Gyromitra esculenta. J. Cancer Res. Clin. Oncol. 93: 109–121.PubMedCrossRefGoogle Scholar
  52. 52.
    von Wright, A., Niskanen, A., and Physalo, H. 1977. The toxicities and mutagenic properties of ethyliden gyromitrin and N-methylhydrazine with Escherichia Coli as test organism. Mutat. Res. 56: 105–110.CrossRefGoogle Scholar
  53. 53.
    Hirono, I., Mori, H., Haga, M., Fujii, M., Yamada, K., Hirata, Y., Takanashi, H., Uchida, E., Hosaka, S., Ueno, I., Matsushima, T., Umezawa, K., and Shirai, A. 1979. Edible plants containing carcinogenic pyrrolizidine alkaloids in Japan. in E. C. Miller, J. A. Miller, I. Hirono, T. Sugimura, and S. Takayama (Eds.) Naturally occurring carcinogens—mutagens and modulators of carcinogenesis. pp. 79–87. Baltimore: University Park Press.Google Scholar
  54. 55.
    Green, N. R., and Savage, J. R. 1978. Screening of safrole, eugenol, their ninhydrin positive metabolites and selected secondary amines for potental mutagenicity. Mutat. Res. 57: 115–121.PubMedCrossRefGoogle Scholar
  55. 56.
    Swanson, A. B., Chambliss, D. D., Blomquist, J. C., Miller, E. C., and Miller, J. A. 1979. The mutagenicities of safrole, estragole, eugenol, trans.-anethole, and some of their known or possible metabolites for Salmonella typhimurium mutants. Mutat. Res. 60: 143–153.PubMedCrossRefGoogle Scholar
  56. 57.
    Rosenkranz, H. S., and Poirier, L. A. 1979. Evaluation of the mutagenicity and DNA-modifying activity of carcinogens and noncarcinogens in microbial systems. J. Natl. Cancer Inst. 62: 873–891.PubMedGoogle Scholar
  57. 58.
    Simmon, V. F. 1979. In vitro assays for recombinogenic activity of chemical carcinogens and related compounds with Saccharomyces cerevisiae D3. J. Natl. Cancer Inst. 62: 901–909.PubMedGoogle Scholar
  58. 59.
    Hirono, I. 1981. Natural carcinogenic products of plant origin. CRC Crit. Rev. Toxicol. 8: 235–277.CrossRefGoogle Scholar
  59. 60.
    Hirayama, T. 1979. Epidemiological evaluation of the role of naturally occurring carcinogens and modulators of carcinogenesis. in E. C. Miller, J. A. Miller, I. Hirono, T. Sugimura, and S. Takayama (Eds.) Naturally occurring carcinogens—mutagens and modulators of carcinogenesis. pp. 359–380. Baltimore: University Park Press.Google Scholar
  60. 61.
    Howe, G. R., Burch, J. D., Miller, A. B., Cook, G. M., Esteve, J., Morrison, P., Gordon, P., Chambers, L. W., Fodor, G., and Winsor, G. M. 1980. Tobacco use, occupation, coffee; various nutrients and bladder cancer. J. Natl. Cancer Inst. 64: 701–713.PubMedGoogle Scholar
  61. 62.
    Pamukcu, A. M., and Bryan, G. T. 1979. Bracken fern, a natural urinary bladder and intestinal carcinogen. in E. C. Miller, J. A. Miller, I. Hirono, T. Sugimura, and E. Takayama (Eds.) Naturally occurring carcinogens—mutagens and modulators of carcinogenesis. pp. 89–99. Baltimore: University Park Press.Google Scholar
  62. 63.
    Evans, I. A. 1976. The bracken carcinogen. in C. E. Searle (Ed.) Chemical carcinogens. ACS Monograph 173. pp. 690–700. Washington, D.C.: American Chemical Society.Google Scholar
  63. 64.
    Umezawa, K., Matsushima, T., Sugimura, T., Hirakawa, T., Tanaka, M., Katoh, Y., and Takayama, S. 1977. In vitro transformation of hamster embryo cells by quercetin. Toxicol. Lett. 1: 175–178.CrossRefGoogle Scholar
  64. 65.
    Bartholomew, R. M., and Ryan, D. S. 1980. Lack of mutagenicity of some phytoestrogens in the Salmonella/mammalian microsome assay. Mutat. Res. 78: 317–321.PubMedCrossRefGoogle Scholar
  65. 66.
    Pamukcu, A. M., Yalciner, S., Hatcher, J. F., and Bryan, G. T. 1980. Quercetin, a rat intestinal and bladder carcinogen present in bracken fern (Pteridium aquilinum). Cancer Res. 40: 3468–3472.PubMedGoogle Scholar
  66. 67.
    Hirono, I., Ueno, I., Hosaka, S., Takanashi, H., Matsushima, T., Sugimura, T., and Natori, S. 1981. Carcinogenicity examination of quercetin and rutin in ACI rats. Cancer Lett. 13: 15–21.PubMedCrossRefGoogle Scholar
  67. 68.
    Pamukcu, A. M., Erturk, E., Yalciner, S., Milli, U., and Bryan, G. T. 1978. Carcinogenic and mutagenic activities of milk from cows fed bracken fern (Pteridium aquilinum). Cancer Res. 38: 1556–1560.PubMedGoogle Scholar
  68. 69.
    Bross, I. D. J., and Tidings, J. 1973. Another look at coffee drinking and cancer of the urinary bladder. Prev. Med. 2: 445–451.PubMedCrossRefGoogle Scholar
  69. 70.
    Wynder, E. L., and Goldsmith, R. 1977. The epidemiology of bladder cancer. A second look. Cancer 40: 1246–1268.PubMedCrossRefGoogle Scholar
  70. 71.
    Howe, G. R., Burch, J. D., Miller, A. B., Cook, G. M., Esteve, J., Morrison, B., Gordon, P., Chambers, L. W., Fodor, G., and Winsor, G. M. 1980. Tobacco use, occupation, coffee, various nutrients and bladder cancer. J. Natl. Cancer Inst. 64: 701–713.PubMedGoogle Scholar
  71. 72.
    MacMahon, B., Yen, S., Trichopoulous, D., Warren, K., and Nardi, G. 1981. Coffee and cancer of the pancreas. N. Engl. J. Med. 304: 630–633.PubMedCrossRefGoogle Scholar
  72. 73.
    Lin, R. S., and Kessler, I. I. 1981. A multifactorial model for pancreatic cancer in man: Epidemiological evidence. JAMA 245: 147–152.PubMedCrossRefGoogle Scholar
  73. 74.
    Martinez, I. 1969. Factors associated with cancer of the esophagus, mouth, and pharynx in Puerto Rico. J. Natl. Cancer Inst. 42: 1069–1094.PubMedGoogle Scholar
  74. 75.
    Stocks, P. 1970. Cancer mortality in relation to national consumption of cigarettes, solid fuel, tea and coffee. Br. J. Cancer 24: 215–225.PubMedCrossRefGoogle Scholar
  75. 76.
    Shennan, D. H. 1973. Renal carcinoma and coffee consumption in 16 countries. Br. J. Cancer 28: 473–474.PubMedCrossRefGoogle Scholar
  76. 77.
    Armstrong, B., and Doll, R. 1975. Environmental factors and cancer incidence and mortality in different countries with special reference to dietary practices. Int. J. Cancer 15: 617–631.PubMedCrossRefGoogle Scholar
  77. 78.
    Armstrong, B., Garrod, A., and Doll, R. 1976. A retrospective study of renal cancer with special reference to coffee and animal protein consumption. Br. J. Cancer 33: 127–136.PubMedCrossRefGoogle Scholar
  78. 79.
    Zeitlin, B. R. 1972. Coffee and bladder cancer. Lancet 1: 1066.PubMedCrossRefGoogle Scholar
  79. 80.
    Wurzner, H. P., Lindstrom, E., Vuatz, L., and Luginbuhl, H. 1977. A 2-year feeding study of instant coffees in rats. II. Incidence and types of neoplasms. Food Cosmet. Toxicol. 15: 289–296.PubMedCrossRefGoogle Scholar
  80. 81.
    Challis, B. C., and Bartlett, C. D. 1975. Possible cocarcinogenic effects of coffee constituents. Nature 254: 532–533.PubMedCrossRefGoogle Scholar
  81. 82.
    Aeschbocher, H. U., and Wurzner, H. P. 1980. An evaluation of instant and regular coffee in the Ames mutagenicity test. Toxicol. Lett. 5: 139–145.CrossRefGoogle Scholar
  82. 83.
    Clarke, C. H., and Wade, M. J. 1975. Evidence that caffeine, 8-methoxypsoralen and steroidal diamines are frameshift mutagens for E. coli K-12. Mutat. Res. 28: 123–125.PubMedCrossRefGoogle Scholar
  83. 84.
    Takayama, S., and Kuwabara, N. 1982. Long-term study on the effect of caffeine in Wistar rats. Gann 73: 365–371.PubMedGoogle Scholar
  84. 85.
    Kihlman, B. A. 1977. Caffeine and chromosomes. New York: Elsevier.Google Scholar
  85. 86.
    Jenssen, D., and Ramel, C. 1978. Factors affecting the induction of micronuclei at low doses of x-rays, MMS and dimethylnitrosamine in mouse erythroblasts. Mutat. Res. 58: 51–65.PubMedCrossRefGoogle Scholar
  86. 87.
    Hirono, I., Kachi, H., and Kato, T. 1970. A survey of acute toxicity of cycads and mortality rate from cancer in the Miyako Islands, Okinawa. Acta Pathol. Jpn. 20: 327–337.PubMedGoogle Scholar
  87. 88.
    Laquer, G. L., and Spatz, M. 1968. Toxicology of cycasin. Cancer Res. 28: 2262–2267.Google Scholar
  88. 89.
    Matsushima, T., Matsumoto, H., Shirai, A., Sawamura, M., and Sugimura, T. 1979. Mutagenicity of the naturally occurring carcinogens cycasin and synthetic methylazoxymethanol conjugates in Salmonella typhimurium. Cancer Res. 39: 3780–3782.PubMedGoogle Scholar
  89. 90.
    International Agency for Research on Cancer. 1974. Thiourea. in IARC Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Man. Vol. 7: Some anti-thyroid and related substances, nitrofurans and industrial chemicals. Lyons, France: International Agency for Research on Cancer.Google Scholar
  90. 91.
    Korpassy, B. 1961. Tannins as hepatic carcinogens. Prog. Exp. Tumor Res. 2: 245–290.PubMedGoogle Scholar
  91. 92.
    Kirby, K. S. 1960. Induction of tumors by tannin extracts. Br. J. Cancer 14: 147–150.PubMedCrossRefGoogle Scholar
  92. 93.
    Litton Bionetics. 1975. Mutagenic evaluation of compound 001401554 tannic acid. Prepared for the Bureau of Foods, Food and Drug Administration under Contract No. 73-56. Kensington, Maryland: Litton Bionetics.Google Scholar
  93. 94.
    Rosenkranz, H. S., and Leifer, Z. 1981. Determining the DNA-modifying activity of chemicals using DNA-polymerase deficient Escherichia coli. Chem. Mutagens 6: 109–147.Google Scholar
  94. 95.
    Grigg, C. W. 1972. Effects of coumarin, pyronin y, 6, 9-dimethyl 2-methyliopurine and caffeine or excision repair and recombination repair in Escherichia coli. J. Gen. Microbiol. 70: 221–230.PubMedGoogle Scholar
  95. 96.
    Radomski, J. L., Greenwald, D., Hearn, W. L., Block, N. L., and Woods, F. M. 1978. Nitrosamine formation in bladder infections and its role in the etiology of bladder cancer. J. Urol. 120: 48–58.PubMedGoogle Scholar
  96. 97.
    Cohen, S. M., Arai, M., Jacobs, J. B., and Friedell, G. M. 1979. Promoting effect of saccharin and DL-tryptophan in urinary bladder carcinogenesis. Cancer Res. 39: 1207–1217.PubMedGoogle Scholar
  97. 98.
    Clayson, D. B., and Garner, R. C. 1976. Carcinogenic aromatic amines and related compounds. in C. E. Searle (Ed.) Chemical carcinogens. ACS Monograph 173. pp. 366–461. Washington, D.C.: American Chemical Society.Google Scholar
  98. 99.
    Bowden, J. P., Chung, K. T., and Andrews, A. W. 1976. Mutagenic activity of tryptophan metabolites produced by rat intestinal microflora. J. Natl. Cancer Inst. 57: 921–924.PubMedGoogle Scholar
  99. 100.
    Clifton, K. N., and Sridharan, B. N. 1975. Endocrine factors and tumor growth. in F. F. Becker (Ed.) Cancer: a comprehensive treatise. Biology of tumors. Vol. 3: Cellular biology and growth. pp. 249–285. New York: Plenum.Google Scholar
  100. 101.
    Pienta, R. J. 1981. Transformation of Syrian hamster embryo cells by diverse chemicals and correlation with their reported carcinogenic and mutagenic activities. Chem. Mutagens 6: 175–202.CrossRefGoogle Scholar

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© Raymond J. Shamberger 1984

Authors and Affiliations

  • Raymond J. Shamberger
    • 1
  1. 1.The Cleveland Clinic FoundationClevelandUSA

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