Cheng Chih Huang

Investigating the association between oral hygiene and head and neck cancer

OBJECTIVES This analysis examined the association between oral hygiene and head and neck cancer (HNC) and whether this association differed by the consumption of alcohol, betel quid, or cigarette and by the genetic polymorphisms of inflammation-related genes. MATERIALS AND METHODS Interviews regarding dental care and oral health were conducted with 317 HNC cases and 296 controls. Genotyping was performed for 6 single nucleotide polymorphisms in IL6, IL10 and PTGS2. RESULTS A positive association was observed between HNC and no regular dental visits (odds ratio (OR)=2.86, 95% confidence interval (CI): 1.47-5.57), brushing teeth <2times/day (OR=1.51, 95% CI: 1.02-2.23), frequent gum bleeding (OR=3.15, 95% CI: 1.36-7.28), and loss of >20 teeth (OR=2.31, 95% CI: 1.05-5.07). Analysis with dental care score (range: 0-4, 4=worst dental care), which combined regular dental visits, toothbrushing, and use of dental floss and mouthwash, showed a positive trend with HNC risk, particularly among alcohol drinkers and cigarette smokers. Multifactor dimensionality reduction analysis divided the study subjects into high- and low-risk group based on combinations of dental care score and IL6 rs1800796 genotypes. Compared to the low-risk group, the high-risk group had an OR of HNC=2.16 (95% CI: 1.44-3.25). CONCLUSIONS This study observed a positive association between poor oral hygiene and HNC, which appeared to differ by alcohol or cigarette consumption and the genotypes of IL6 rs1800796. Further investigations are needed to determine whether poor oral hygiene is a cause for HNC or a surrogatemarker of an unhealthy lifestyle that increases the risk of HNC.

The interplay between alcohol consumption, oral hygiene, ALDH2 and ADH1B in the risk of head and neck cancer

Alcohol consumption is an established risk factor for head and neck cancer (HNC). The major carcinogen from alcohol is acetaldehyde, which may be produced by humans or by oral microorganisms through the metabolism of ethanol. To account for the different sources of acetaldehyde production, the current study examined the interplay between alcohol consumption, oral hygiene (as a proxy measure for the growth of oral microorganisms), and alcohol‐metabolizing genes (ADH1B and ALDH2) in the risk of HNC. We found that both the fast (*2/*2) and the slow (*1/*1 + *1/*2) ADH1B genotypes increased the risk of HNC due to alcohol consumption, and this association differed according to the slow/non‐functional ALDH2 genotypes (*1/*2 + *2/*2) or poor oral hygiene. In persons with the fast ADH1B genotype, the HNC risk associated with alcohol drinking was increased for those with the slow/non‐functional ALDH2 genotypes. For those with the slow ADH1B genotypes, oral hygiene appeared to play an important role; the highest magnitude of an increased HNC risk in alcohol drinkers occurred among those with the worst oral hygiene. This is the first study to show that the association between alcohol drinking and HNC risk may be modified by the interplay between genetic polymorphisms of ADH1B and ALDH2 and oral hygiene. Although it is important to promote abstinence from or reduction of alcohol drinking to decrease the occurrence of HNC, improving oral hygiene practices may provide additional benefit.

Allergies and Risk of Head and Neck Cancer: An Original Study plus Meta-Analysis

Background Although the relationship between allergy and cancer has been investigated extensively, the role of allergy in head and neck cancer (HNC) appears less consistent. It is not clear whether allergies can independently influence the risk of HNC in the presence of known strong environmental risk factors, including consumption of alcohol, betel quid, and cigarette. Methods The current paper reports results from: 1) an original hospital-based case-control study, which included 252 incident cases of HNC and 236 controls frequency-matched to cases on sex and age; and 2) a meta-analysis combining the results of the current case-control study and 13 previously published studies (9 cohort studies with 727,569 subjects and 550 HNC outcomes and 5 case-control studies with 4,017 HNC cases and 10,928 controls). Results In the original case-control study, we observed a strong inverse association between allergies and HNC [odds ratio = 0.41, 95% confidence interval (CI): 0.27–0.62]. The meta-analysis also indicated a statistically significant inverse association between HNC and allergies [meta-relative risk (RR) = 0.76, 95% CI: 0.63–0.91], particularly strong for allergic rhinitis (meta-RR = 0.55, 95% CI: 0.40–0.76). In addition, the inverse association between allergies and HNC was observed only among men (meta-RR = 0.67, 95% CI: 0.54–0.84) but not among women (meta-RR = 0.98, 95% CI: 0.81–1.18). Conclusions These findings suggest that immunity plays an influential role in the risk of HNC. Future studies investigating immune biomarkers, including cytokine profiles and genetic polymorphisms, are warranted to further delineate the relationship between allergies and HNC. Understanding the relationship between allergies and HNC may help devise effective strategies to reduce and treat HNC.

Arginine deprivation as a new treatment strategy for head and neck cancer

OBJECTIVES Arginine is a nonessential amino acid which can regulate tumor growth. Argininosuccinate synthetase (ASS) is the rate-limiting enzyme for de novo arginine production. The expression pattern of ASS and the feasibility of arginine deprivation therapy in head and neck cancer have not been investigated. MATERIALS AND METHODS The growth-inhibitory effect of arginine deprivation therapy was assessed either by proliferation assay with head and neck cancer cells cultured in arginine-free medium, or by tetrazolium/formazan dye assay with cells treated with an arginine-depleting drug (arginine deiminase, ADI). The tumor ASS status of 73 oral squamous carcinoma (OSCC) patients was then evaluated immunohistochemically and subsequently correlated with the corresponding clinicopathological parameters. RESULTS Head and neck cancer cells cultured in arginine-free medium either completely stopped proliferating, or proliferated minimally. In addition, ADI treatment inhibited the growth of all 8 head and neck cancer cell lines to different degrees. Although cellular ASS level did not correlate well with ADI-sensitivity among these cell lines, knockdown of endogenous ASS potentiated the growth-inhibitory effect of ADI in each individual cell line (FaDu and OEC-M1). In multivariable analysis, high tumor ASS level independently predicted an unfavorable disease-free survival in OSCC patients. CONCLUSION High tumor ASS status is an independent variable predicting a poor disease-free survival in OSCC patients. Arginine deprivation therapy may potentially be used as a new approach to treat head and neck cancer.

Tea Consumption and Risk of Head and Neck Cancer

Background The current study evaluated the association between tea consumption and head and neck cancer (HNC) in Taiwan, where tea is a major agricultural product and a popular beverage. Methods Interviews regarding tea consumption (frequency, duration, and types) were conducted with 396 HNC cases and 413 controls. Unconditional logistic regression was performed to estimate the odds ratio (OR) and 95% confidence interval (CI) of HNC risk associated with tea drinking, adjusted for sex, age, education, cigarette smoking, betel quid chewing, and alcohol drinking. Results A reduced HNC risk associated with tea drinking (OR for every cup per day = 0.96, 95% CI: 0.93–0.99; OR for ≧5 cups per day = 0.60, 95% CI: 0.39–0.94) was observed. The association was especially significant for pharyngeal cancer (OR for every cup per day = 0.93, 95% CI: 0.88–0.98; OR for ≧5 cups per day = 0.32, 95% CI: 0.16–0.66). A significant inverse association between HNC and tea consumption was observed particularly for green tea. Conclusions This study suggests that tea drinking may reduce the risk of HNC. The anticancer property of tea, if proven, may offer a natural chemopreventive measure to reduce the occurrence of HNC.

Human papilloma virus detection in neoplastic and non-neoplastic nasopharyngeal tissues in Taiwan

Background Human papilloma virus (HPV) has been implicated in the carcinogenesis and prognosis of certain head and neck cancers. Whether it also has a role in the pathogenesis of nasopharyngeal carcinoma (NPC) in Taiwan is unclear. Methods Detection and genotyping of HPVs were performed in 43 primary NPCs (one WHO-I and 42 WHO-II/III) and 40 nasopharyngeal controls using PCR-based HPV genotyping arrays. Localisation of high-risk HPV and Epstein–Barr virus genomes was performed in another 46 primary NPCs (five WHO-I and 41 WHO-II/III) and seven paired metastatic WHO-II/III NPCs using in situ hybridisation. Results In the HPV genotyping cohort, oncogenic HPVs were detected equally in WHO-II/III NPCs (31%, 13/42) and nasopharyngeal controls (35%, 14/40). Tumour high-risk HPV status did not correlate with the prognosis of patients with NPC. In the high-risk HPV in situ hybridisation cohort, 14 (88%) of the 16 oncogenic HPV-positive WHO-II/III NPCs showed a unique cytoplasmic/perinuclear staining pattern, which is distinct from the typical dot/punctate nuclear staining pattern indicating HPV genome integration. In addition, oncogenic HPVs were not always retained in NPC cells during the process of metastasis. Conclusions This study does not support an association between oncogenic HPV and the carcinogenesis or prognosis of WHO-II/III NPCs in Taiwan.

Life expectancy and expected years of life lost to oral cancer in Taiwan: A nation-wide analysis of 22,024 cases followed for 10 years

OBJECTIVES This analysis examined the life expectancies (LE) and expected years of life lost (EYLL) in relation to oral cancer in Taiwan. MATERIALS AND METHODS A semi-parametric extrapolation method was applied to estimate gender, age, histology, subsite, and stage stratified LE, EYLL of 22,024 pathologically verified oral cancer patients retrospectively recruited from the National Cancer Registry of Taiwan during 2002-2009, who were followed up to 2011. RESULTS The patients were predominantly male 20,101, (91.3%), and over 80% were less than 65years old. The mean age at diagnosis of males was younger than that of females (52.73years vs. 60.76years). The LE after diagnosis was longer among females than males (15.26years vs. 12.73years), with a smaller loss of the corresponding EYLL (8.88years vs. 14.05years), which prevails after stratification by age and stage. More than half of the oral cancer cases were diagnosed at a later stage, with 2921 cases (13.3%) of stage III and 8488 (38.5%) of stage IV. The five-year overall survival rate of oral cancer for stages I, II, III, and IV were 78.98%, 69.38%, 54.62%, and 36.17%, respectively. The earlier the diagnosis, the longer the life expectancy and the smaller the EYLL. CONCLUSIONS We concluded that early detection and early intervention of oral cancer can prolong life expectancy and reduce the years of life lost, indicating the importance of proactive screening and oral hygiene.

Investigating the Association between Alcohol and Risk of Head and Neck Cancer in Taiwan

Although alcohol is an established risk factor of head and neck cancer (HNC), insufficiencies exist in the literature in several aspects. We analyzed detailed alcohol consumption data (amount and type of alcoholic beverage) of 811 HNC patients and 940 controls to evaluate the association between alcohol and HNC by HNC sites and by genotypes of ADH1B and ALDH2. Alcohol was associated with an increased HNC risk in a dose-response relationship, with the highest risk observed for hypopharyngeal cancer, followed by oropharyngeal and laryngeal cancers. Liquor showed a stronger positive association with HNC than beer and wine. The highest HNC risk occurred in individuals with the slow ADH1B and slow/non-functional ALDH2 genotype combination. In our study population, 21.8% of HNCs, 55.7% of oropharyngeal cancers, and 89.1% of hypopharyngeal cancers could be attributed to alcohol. Alcohol accounted for 47.3% of HNCs among individuals with the slow ADH1B and slow/non-functional ALDH2 genotype combination. The HNC risk associated with alcohol became comparable to that of never/occasional drinkers after ten or more years of cessation from regular alcohol drinking. In conclusion, alcohol use is associated with an increased HNC risk, particularly for individuals with slow ethanol metabolism. HNC incidence may be reduced by alcohol cessation.

Hyaluronan synthase 3 mediated oncogenic action through forming inter-regulation loop with tumor necrosis factor alpha in oral cancer

Hyaluronan (HA) is a major extracellular matrix component. However, its role and mediation in oral cancer remains elusive. Hyaluronan synthase 3 (HAS3), involved in pro-inflammatory short chain HA synthesis, was the predominant synthase in oral cancer cells and tissues. HAS3 overexpression significantly increased oral cancer cell migration, invasion and xenograft tumorigenesis accompanied with the increased expression of tumor necrosis factor alpha (TNF-α) and monocyte chemoattractant protein 1 (MCP-1). Conversely, HAS3 depletion abrogated HAS3-mediated stimulation. HAS3 induced oncogenic actions partly through activating EGFR-SRC signaling. HAS3-derived HA release into extracellular milieu enhanced transendothelial monocyte migration and MCP-1 expression, which was attenuated by anti-HAS3 antibodies or a HAS inhibitor, 4-Methylumbelliferone (4-MU). The NF-κB-binding site III at -1692 to -1682 bp upstream from the transcript 1 start site in HAS3 proximal promoter was the most responsive to TNF-α-stimulated transcription. ChIP-qPCR analysis confirmed the highest NF-κB-p65 enrichment on site III. Increased HAS3 mRNA expression was negatively correlated with the overall survival of oral cancer patients. A concomitant increase of TNF-α, a stimulus for HAS3 expression, with HAS3 expression was not only associated with lymph node metastasis but also negated clinical outcome. Together, HAS3 and TNF-α formed an inter-regulation loop to enhance tumorigenesis in oral cancer.

A Comprehensive Analysis on the Association between Tobacco-Free Betel Quid and Risk of Head and Neck Cancer in Taiwanese Men.

Objectives Although betel quid (BQ) is an established risk factor of head and neck cancer (HNC), insufficiencies exist in the literature regarding the dose-response, BQ types, HNC sites, and BQ cessation. The current study was conducted to fill these insufficiencies. Materials and Methods A hospital-based case-control study was conducted to evaluate the association between BQ and HNC. In-person interview was conducted to collect data on BQ chewing. The current analysis included 487 men newly diagnosed with HNC and 617 male controls who were frequency-matched to the cases by age. The association between BQ and HNC was assessed using multivariable unconditional logistic regression. Results Ever BQ chewing was associated with an increased HNC risk regardless of the BQ types. A non-linear positive association between BQ and HNC was observed, with a steep rise in HNC risk for the first 5 pack-years or 200,000 minutes of BQ consumption. Every year of BQ cessation was associated with a 2.9% reduction in HNC risk; however, the risk did not reduce to the level of non-BQ chewers even after 20 years of BQ cessation. Eliminating BQ chewing may prevent 51.6% of HNCs, 62.6% of oral cancers, and 41.3% of pharyngeal cancers in Taiwan. Conclusion Our results supported the positive association between BQ and HNC. BQ cessation is effective in reducing HNC risk and should be encouraged. Because BQ cessation may not reduce the HNC risk to the level of non-BQ chewers, it is important to prevent the initiation of BQ chewing.