口腔黏膜下纖維化之流行病學研究(3/3)

Oral submucous fibrosis (OSF) is a chronic disease of oral mucosa, It can involve any part of
oral cavity, sometimes, even the pharynx and esophagus. Its main characteristic is the abnormal
accumulation of submucous collagen. Eventually, it may lead to oral mucosal stiffness trismus
and dysphagia. These will severely impair patients’ eating, speaking, accessment of dental
treatment, and quality of life. OSF is also an oral premalignancy. According to several long term
follow-up studies, 2.3%~33.3% OSF will progress into oral cancer.
The etiology of OSF remains unclear, and there is no effective clinical treatment for OSF.
Prevention is more important than treatment for OSF. Most studies suggest betel quid chewing is
an important risk factor for OSF, but only a small proportion of betel quid chewers get OSF.
This implies that genetic susceptibility may also play an important role in the etiology of OSF.
This project is to examine associations with OSF for genetic polymorphisms of repair gene,
collagenase gene and cystatin gene, and to compare risk factors for OSF and oral cancer.
Study subjects were recruited from hospital and communities. A total of 77 oral cancer
patients, 167 OSF cases, 111 healthy betel quid chewers was recruited from the dental clinic of
NTUH as our hospital subjects. We also recruited 173 healthy betel quid chewers from Makung,
Chutung, Potzu, Kaoshu and Sanchi as our community controls. Standardized personal
interviews-based on structure questionnaire was carried out to obtain information on risk factors
for OSF and oral cancer. Polymerase chain reaction and restriction fragment length
polymorphism was used to genotype the genes of collagen and collagenases and repair gene.
Multiple logistic regression analysis was used to estimate multivariate-adjusted odds rations
with their 95% confidence intervals of various risk factors.
Among the 12 candidate gene loci, a biallelic promotor-region polymorphism of the TNFA
gene at position –308 was found to have association with OSF. As precious study demonstrated
the rare allele, TNF*2, having increased promotor function compared with the common allele,
TNF*1 and the transcriptional induction of TNF-α in collagenase, we found the *2/ *2
genotype is more protective with an odds ratio of 0.4 (95% CI=0.2-0.7). This result is in keeping
with a protective role of TNF-α against OSF. Moreover, the association between OSF and
TNFA gene mentioned before was found to be independent of oral cancer.