Krogh P
Department of Microbiology, Royal Dental College, Copenhagen, Denmark.
Acta Odontol Scand. 1990 Feb;48(1):85-8. doi: 10.3109/00016359009012738.
Oral leukoplakias, particularly non-homogeneous types, are often invaded by yeasts, with Candida albicans being the dominant species. The more advanced precancerous leukoplakia lesions yield more rarely occurring biotypes of C. albicans, suggesting a causal role for these biotypes in the malignant transformation. N-nitroso-benzylmethylamine (NBMA) is a compound able to induce carcinoma of the esophagus and the oral cavity in the rat. The catalytic potential of yeasts, isolated from leukoplakia lesions and from normal mucosa, to produce NBMA from the precursors N-benzyl-methylamine and nitrite was assessed at pH 6.8. The yeast strains differed in nitrosation potential, ranking from 0 to 1.2 micrograms NBMA/10(6) cells. C. albicans strains of the more rarely occurring biotypes showed the highest nitrosation potential, whereas C. tropicalis, C. parapsilosis, and Torulopsis glabrata were ranked lower. Strains with high nitrosation potential were generally isolated from lesions with more advanced precancerous changes. Thus, further evidence is provided supporting the hypothesis that yeasts play a causal role in oral cancer by means of endogenous nitrosamine production.
口腔白斑，尤其是非均质型白斑，常被酵母菌侵袭，白色念珠菌是主要菌种。癌前病变程度越严重的白斑，白色念珠菌的生物型出现频率越低，这表明这些生物型在恶性转化中起因果作用。N-亚硝基苄基甲胺（NBMA）是一种能在大鼠体内诱发食管癌和口腔癌的化合物。在pH 6.8条件下，评估了从白斑病变和正常黏膜分离出的酵母菌从前体N-苄基甲胺和亚硝酸盐产生NBMA的催化潜力。酵母菌株的亚硝化潜力不同，范围为0至1.2微克NBMA/10⁶个细胞。出现频率较低的生物型白色念珠菌菌株显示出最高的亚硝化潜力，而热带念珠菌、近平滑念珠菌和光滑球拟酵母的亚硝化潜力较低。具有高亚硝化潜力的菌株通常从癌前病变更严重的病变中分离得到。因此，进一步的证据支持了酵母菌通过内源性亚硝胺产生在口腔癌中起因果作用的假说。
