Genomic instability in oral squamous cell carcinoma: relationship to betel-quid chewing

Triclosan (TCS) affects the level of DNA methylation in the human oral squamous cell carcinoma (SCC-15) cell line in a nontoxic concentration

The oral cancer is presumably caused by genetic factors and exposure to substances derived from cosmetics and disinfectants. Triclosan (TCS) is widely spread in many consumer products and oral care products. Since TCS can affect DNA methylation, which is one of the key mechanisms of gene expression that may lead to cancerogenesis, it is necessary to study this mechanism in oral cell carcinoma. The aim of the present study was to evaluate the impact of TCS on metabolic parameters, oxidative stress, gene expression, and DNA methylation and hydroxymethylation in the SCC-15 cell line. The experiments have shown TCS toxicity to SCC-15 cells only in the highest concentrations of 50 and 100 µM. TCS in a wide range of concentrations increases ROS production and caspase-3 activity. Our experiments have shown that TCS in the nontoxic concentrations of 10 µM exerts an impact on SOD2 mRNA expression and SOD activity in the SCC-15 cell line. Finally, our experiments have demonstrated that 6-h treatment with TCS decreases the mRNA expression of DNMT3A and DNMT3B. After 72-h exposure to TCS, an increased level of 5-methylcytosine and 5-hydroxymethylcytosine was observed in the SCC-15 cell line, but it was abolished by the NAC treatment. However, it is very likely that these results can be an effect of TET enzyme activity, especially in the case of the decrease in 5mC and the increase in 5hmC after the 48-h exposure to TCS, which was accompanied with a decrease in the mRNA expression of DNMT3A and DNMT3B.

Oral cancer in a 5-year-old boy: a rare case report and review of literature

Oral cancer in children is rare. Diagnosis may be delayed as a result of confusion with reactive lesions. Furthermore, cancer staging, with or without bony invasion, can be complicated during tooth eruption. Literature on pediatric oral cancers is lacking, making determination of the possible etiopathology difficult. We describe an exceptional case of a 5-year-old male child who presented with anterior maxillary gingival pseudoepitheliomatous hyperplasia that progressed to carcinoma cuniculatum with invasive oral squamous cell carcinoma (OSCC). Because of the interesting timing of events, we hypothesize that human papillomavirus (HPV) inoculation through cutaneous squamous papilloma played a contributory role. A review of similar case reports in the literature is included. Biopsy of suspicious oral lesions should not be delayed because of the young age of the patient. Atypical hyperplasia should include squamous cell carcinoma (SCC) in the differential diagnoses. For surgical management of aggressive lesions during the mixed dentition, permanent successors should be included in the surgical margins to prevent recurrence.

Genetic analysis of surgical margins in oral cavity cancer

BACKGROUND

A histological, tumour-free surgical margin does not guarantee recurrence-free survival in patients with cancer. This study investigated the association between microsatellite alteration in tumour-free surgical margins and local recurrence in patients with oral cavity squamous cell carcinoma.

METHODS

Patients with histologically confirmed oral cavity squamous cell carcinoma were enrolled in this prospective study. Cancerous specimens, corresponding surgical margins and peripheral blood were obtained. Microsatellite alteration was investigated using six dinucleotide microsatellite markers. All samples were amplified by PCR, followed by automatic fragment analysis.

RESULTS

Microsatellite alteration was identified in 100 specimens (69·0 per cent) from 145 patients. Among them, 85 specimens carried loss of heterozygosity, whereas 55 had microsatellite instability (MSI). Patients with MSI at the surgical margin had a higher risk of local recurrence on multivariable analysis (odds ratio 7·17, 95 per cent c.i. 3·49 to 14·73).

CONCLUSION

Molecular assessment of surgical margins can help identify patients at risk of local recurrence.

"Omics" in oral cancer: New approaches for biomarker discovery

OBJECTIVES

In this review paper, we explored the application of "omics" approaches in the study of oral cancer (OC). It will provide a better understanding of how "omics" approaches may lead to novel biomarker molecules or molecular signatures with potential value in clinical practice. A future direction of "omics"-driven research in OC is also discussed.

METHODS

Studies on "omics"-based approaches [genomics/proteomics/transcriptomics/metabolomics] were investigated for differentiating oral squamous cell carcinoma,oral sub-mucous fibrosis, oral leukoplakia, oral lichen planus, oral erythroplakia from normal cases. Electronic databases viz., PubMed, Springer, and Google Scholar were searched.

RESULTS

One eighty-one studies were included in this review. The review shows that the fields of genomics, transcriptomics, proteomics, and metabolomics-based marker identification have implemented advanced tools to screen early changes in DNA, RNA, protein, and metabolite expression in OC population.

CONCLUSIONS

It may be concluded that despite advances in OC therapy, symptomatic presentation occurs at an advanced stage, where various curative treatment options become very limited. A molecular level study is essential for detecting an OC biomarker at an early stage. Modern "Omics" strategies can potentially make a major contribution to meet this need.

Impact of microsatellite alteration in surgical margins on local recurrence in oral cavity cancer patients

The aim of this study was to investigate the association between microsatellite alteration in the surgical margins and local recurrence of oral cavity squamous cell carcinoma patients. Surgical specimens confirmed by pathological examination and corresponding surgical margins were collected from 120 oral cavity squamous cell carcinoma patients. Ten microsatellite markers were examined in the tumor specimens and paired surgical margins, which proved to be negative on pathological assessment. The specimens and surgical margins were amplified by polymerase chain reaction followed by computerized analysis. Forty-two specimens (35.0 %) with microsatellite instability (MSI) in at least one marker were found, and more than half of the specimens (n = 73, 60.8 %) had loss of heterozygosity (LOH) in at least one marker. Although MSI and LOH were not associated with the prognosis of oral cavity squamous cell carcinoma patients, presence of MSI in the tumor-free surgical margins increased the risk of local recurrence (hazard ratio: 9.549; 95 % confidence interval: 4.143-22.01). Genetic analysis of tumor-free surgical margins is a useful tool for identifying oral cavity squamous cell carcinoma patients who are vulnerable to local recurrence.

Microsatellite alteration in head and neck squamous cell carcinoma patients from a betel quid-prevalent region

We investigated the frequency of microsatellite alteration and their impact on survival in head and neck squamous cell carcinoma patients from an endemic betel quid chewing area. We collected 116 head and neck squamous cell carcinoma specimens along with corresponding surgical margins which were confirmed by pathological examination. Ten oligonucleotide markers were chosen for the assessment of microsatellite alteration. The specimens were amplified by polymerase chain reaction followed by automatic fragment analysis. There were 44 specimens (37.9%) with microsatellite instability (MSI) in at least one marker while more than half of the specimens (n = 68, 58.6%) had loss of heterozygosity (LOH) in at least one marker. Though MSI/LOH was not correlated with the survival of head and neck squamous cell carcinoma patients, presence of MSI in the tumor-free surgical margins was associated with local recurrence (odds ratio: 15.14; 95% confidence interval: 6.451 ~ 35.53; P < 0.001). Genomic assessment of surgical margin can help surgeons to identify head and neck squamous cell carcinoma patients who are at risk of developing local recurrence in a betel quid-prevalent region.

Positron emission tomography-computed tomography versus positron emission tomography-magnetic resonance imaging for diagnosis of oral squamous cell carcinoma: A pilot study

Diagnostic imaging of head and neck cancer has made enormous progress during recent years. Next to morphological imaging modalities (computed tomography [CT] and magnetic resonance imaging [MRI]), there are also hybrid imaging systems that combine functional and morphological information (positron emission tomography [PET]/CT and PET/MRI). The aim of this study was to compare the diagnostic accuracy of PET/MRI in the diagnosis of head and neck cancer with other imaging modalities (MRI, CT, PET/CT). Ten patients (nine male and one female) with histologically proven oral squamous cell carcinoma participated in an 18 F-FDG-PET/CT scan and an additional 18 F-FDG PET/MRI scan prior to surgery. The morphological and functional results were compared with the histological results. Inclusion criteria were histologically proven oral squamous cell carcinoma and no prior surgical intervention, medical therapy, or local external radiation. There was no significant correlation between tumor differentiation and maximum standard uptake values. Functional imaging showed a slightly better correlation with the measurement of the maximal tumor diameter, whereas pure morphological imaging showed a better correlation with the measurement of infiltration depth. Only with PET/MRI could correct lymph node staging be reached; the other imaging tools showed false-negative or false-positive results. In conclusion, we showed in our limited patient cohort that PET/MRI is superior to the morphological imaging modalities, especially for lymph node staging.

Fingerprinting genomic instability in oral submucous fibrosis

BACKGROUND

Oral submucous fibrosis (OSF) is a high-risk pre-cancerous condition where 7-13% of these patients develop head and neck squamous cell carcinoma (HNSCC). To date there is no cancer predictive markers for OSF patients. Genomic instability hallmarks early genetic events during malignant transformation causing loss of heterozygosity (LOH) and chromosomal copy number abnormality. However, to date there is no study on genomic instability in OSF. Although this condition is known as a high-risk pre-cancerous condition, there is no data regarding the genomic status of this disease in terms of genetic susceptibility to malignant transformation.

METHODS

In this study, we investigated the existence of genetic signatures for carcinogenesis in OSF. We employed the high-resolution genome-wide Affymetrix Mapping single nucleotide polymorphism microarray technique to 'fingerprint' global genomic instability in the form of LOH in 15 patient-matched OSF-blood genomic DNA samples.

RESULTS

This rapid high-resolution mapping technique has revealed for the first time that a small number of discrete hot-spot LOH loci appeared in 47-53% of the OSF tissues studied. Many of these LOH loci were previously identified regions of genomic instability associated with carcinogenesis of the HNSCC.

CONCLUSION

To our knowledge, this is the first evidence that genomic instability in the form of LOH is present in OSF. We hypothesize that the genomic instability detected in OSF may play an important role in malignant transformation. Further functional association studies on these putative genes may reveal potential predictive oral cancer markers for OSF patients.

Cancer and forensic microsatellites

Although not directly related, circumstances do occur in forensic investigations whereby cancer studies and forensic science cross paths. This review takes a look at the circumstances under which this may occur, and investigates some potential problems that can arise when tumor tissue is submitted for DNA profile analysis. A background to the underlying molecular biology of tumors is described, highlighting the genetic instabilities that are observed in DNA sequences of similar or identical primary structure to the short tandem repeat markers used in forensic DNA profiling kits.

Visual screening of oral cavity cancer: The role of otolaryngologists

OBJECTIVES

Because most screening was done by dentists, the purpose of this prospective cohort study was to evaluate the effectiveness of oral visual screening by otolaryngologists. In addition, we wanted to determine which group of enrolled patients was at potential risk of contracting oral cancer.

METHODS

All male patients age > or =18 years who visited our clinic received oral mucosal screening. Basic data, including personal habits, were also obtained. A multivariate logistic regression model was devised to determine relevant risk factors for developing oral cancer.

RESULTS

A total of 5,825 patients were enrolled in this study. Positive findings were found in 226 patients (3.9%). One hundred seventy-two patients received biopsy and 131 patients were proven to have oral cancer (sensitivity rate: 76.2%). The results showed that those who smoked, consumed alcohol, and chewed betel quid on a regular basis were most likely to contract oral cancer (odds ratio = 49.81, 95% confidence interval = 29.38-84.42).

CONCLUSIONS

The otolaryngologists involved in this study successfully performed the oral screening. The sensitivity and specificity rates were both satisfactory. We suggest that those who are habitual cigarette smokers, alcohol consumers, and betel quid chewers should receive oral mucosal screening regularly so that potential oral cancer can be detected as early as possible.

Panmucositis and chemosensitisation associated with betel quid chewing during dose-dense adjuvant breast cancer chemotherapy

PURPOSE

The severity of chemotherapy-induced oral mucositis has previously been reported to be greater in patients who chew betel quid (areca), an addictive habit shared by hundreds of millions of individuals worldwide. Here, we report a case of fulminant panmucositis complicating dose-dense adjuvant breast cancer treatment in a betel-chewing patient without evidence of other risk factors.

METHODS

Grade IV mucositis was triggered by the initial use of standard-dose anthracycline chemotherapy, and involved not only the mouth but also the genital and anal mucosa, as well as other severe non-mucosal toxicities.

RESULTS

Despite subsequent treatment with dose-reduced CMF and docetaxel regimens-which are seldom associated with mucosal toxicity at these dose intensities in the absence of neutropenia-high-grade oral mucositis continued to complicate the therapeutic course.

CONCLUSION

These observations suggest that the potentiation of chemotherapy-induced mucositis by quid chewing may not be mediated solely by local effects on the oral epithelium, but also involves the systemic absorption of toxic chemosensitising molecules.

Frequent microsatellite alterations of chromosome locus 4q13.1 in oral squamous cell carcinomas

BACKGROUND

Studies have revealed that losses of chromosome 4q24-25 regions are frequent in cancers including head and neck squamous cell carcinoma. Our previous comparative genomic hybridization analysis showed extensive losses of chromosome arm 4q in oral squamous cell carcinoma (OSCC).

METHODS

To be more precise in mapping the potential regions of allelic losses and to understand the microsatellite instability (MSI) on 4q involving in oral pathogenesis, we performed allelotypings using eight polymorphic markers. Microsatellite analyses were first performed on 100 randomly selected controls to confirm the high informative rates of markers. Twenty OSCC tissues were microdissected from surgical specimens for microsatellite alterations (MA) analysis.

RESULTS

MA was observed in 95% OSCC cases. The most eminently altered locus was 4q13.1 (75%), followed by 4q22.2 and 4q32.1 (55%). Allelic losses also occurred most frequently on these loci. Thirty-five percent cases had MA spanning 4q13.1 to 4q21.1. MSI occurred in 35% OSCC, at a lesser extent compared with allelic losses. The most common locus for MSI was 4q21.2 (20%). In addition, 4q MSI was significantly associated with the lymph node metastasis of OSCC (P = 0.01). So far, most tumor suppressor genes on 4q have not been specified.

CONCLUSION

Our results were additive to previous findings and proposed novel scenario of suppressor loci located at 4q13.1-21.1 whose inactivation could be important for progression of OSCC.

Determinants of old-age mortality in Taiwan

Relationships among socio-demographic characteristics, general assessments of health, and old-age mortality have been well established in developed countries. There is also increasing focus on the connection between early-life experiences and late-life health. This study tests these and other associations using representative survey data from Taiwan. Survey data on the 60 and over population (N = 4049) in 1989, 1993, and 1996 are linked to 1989-1999 data from a national death registry. Survival is modeled using Gompertz regression and both fixed and time-varying covariates. Possible effects of Taiwan's Universal Health Insurance Program are tested by coding observations as pre- or post-insurance. Some results replicate findings from developed countries; others are new. Contemporaneous education effects on survival are attenuated after introducing some indicators of health from a previous period. Functional and global assessments of health have stronger associations with survival than reports of other health-related characteristics. Mainlanders have higher survival than others. Increases in survival over the 1990s were concentrated among those with the greatest number and severity of functional limitations. This pattern may be an indication of better access to health care or changes in longer-run, but unmeasured, determinants of old-age mortality.