Possible mycological etiology of oral mucosal cancer: catalytic potential of infecting Candida aibicans and other yeasts in production of N-nitrosobenzylmethylamine

Abstract

Yeasts were isolated from 12 cases of oral precancerous lesions (leukoplakia and erythroleukoplakia) by sampling the lesion as well as normal mucosa of each patient, yielding 21 strains of Candida albicans belonging to 15 biotypes, two strains of C. tropicalis, one strain of C. parapsilosis and two strains of Torulopsis glabrata. Biopsies were obtained from the lesions for histologic examination. The catalytic potential of the yeast strains to form N-nitrosobenzylmethylamine (NBMA) from the precursors N-benzylmethylamine and nitrite was assessed at pH 6.8. The NBMA produced was identified and quantitated by h.p.l.c. and confirmed by g.c.-m.s. Nitrosation rates were calculated as total nitrosamine subtracted the chemically produced nitrosamine, and related to number of yeast cells. The yeast strains differed in nitrosation potential (P less than 0.001), ranking from 0 to 1.2 micrograms NBMA/10(6) cells. Candida albicans strains, belonging to the biotypes 051, 147, 151, 153, 157 and 353, which constitute more rarely occurring biotypes, exhibited the highest nitrosation potential. Candida tropicalis, C. parapsilosis and T. glabrata were ranked lower. Strains with high nitrosation potential were generally isolated from lesions with more advanced precancerous changes. The yeast cells were present in the superficial part of the epithelium of the lesions as branching mycelium, and in some cases extending from the mucosal surface to the deeper epithelial cell layers. This might represent a fungal transportation system which could channel precursors in the saliva at the mucosal surface to the deeper part of the epithelium where the produced nitrosamine could be deposited. Thus, further evidence is provided supporting the hypothesis that certain strains of C. albicans and of other yeasts play a causal role in the development of oral cancer, by means of endogenous nitrosamine production.

PCR Fingerprinting of Candida albicans Associated with Chronic Hyperplastic Candidosis and Other Oral Conditions

“…In addition, a correlation between histologically confirmed fungal invasion and epithelial dysplasia in oral mucosal lesions has been reported (1). Furthermore, the ability of certain C. albicans strains to promote neoplastic changes (22) and to produce carcinogenic nitrosamines from saliva (9) has highlighted the potential role of candida in malignant transformation.…”

Research Progress on the Relationship Between Oral Microbial Community and Tumor

“…Biomembrane on tumor surface of oral squamous carcinoma contains more aerobic and anaerobic bacteria than other organisms [11,12] . Compared with healthy mucosa, pathological changes in tumor tissues lead to changes in bacterial colonization, and microbial com mu n it ies a l so c h a nge cor re s pond i ng ly.…”

“…Krogh et al [12] noted significantly increased amounts of Veillonella, Cyperenal, Porphyromonas, Actinomyces, Clostridium, Haemophilus, Enterobacter, and Streptococcus on surface of squamous cell carcinoma tissues. Simultaneously, some rare bacteria, such as Plantibacter flavus, Clavibacter michiganensis, and Thermus, exist in deep tissues of oral squamous carcinoma [14,15] .…”

Lichen plan buccal : histoire naturelle et transformation maligne

“…Plus récemment Van der Meij et coll. [56] ont réalisé une autre revue de la littérature sur une période allant 1977 à 1997 avec les mêmes critères que Krutchkoff et coll. [26] .…”