Adenomatous polyposis coli gene mutation and decreased wild-type p53 protein expression in oral submucous fibrosis: a preliminary investigation

Oral submucous fibrosis: An overview of a challenging entity

The oral cavity is considered to be a mirror of the body's health, as it reflects the manifestations of various systemic disorders. Most of the oral mucosa is derived embryologically from an invagination of ectoderm and thus, like other similar orifices, it may become involved in the disorders that are primarily associated with the skin. Oral submucous fibrosis is one of the commonest precancerous conditions of the oral mucosa involving any part of the oral cavity resulting in tissue scarring, dysphagia and trismus. It is a collagen-related disorder characterized by excessive fibrosis in the oral submucosa, hyalinization and degenerative changes in the muscles. This disease has become a challenging entity for dermatologists due to resemblance of its features to various mucocutaneous conditions. An improper diagnosis can lead to wrong treatment and additional complications. Dermatologists need to be aware of the characteristic features of this disease which can distinguish it from other similar conditions. This review aims to focus on the detailed aspects of oral submucous fibrosis including its historical background, etiological factors, pathogenesis, clinical features, differential diagnosis, investigations, management and future perspectives.

Apc-Mutant Kyoto Apc Delta (KAD) Rats Are Susceptible to 4-NQO-Induced Tongue Carcinogenesis

Despite widening interest in the possible association between infection/inflammation and cancer development, knowledge of this issue in relation to oral cancer remains inadequate. This study aimed to determine the susceptibility of Apc-mutant Kyoto Apc Delta (KAD) rats, which are vulnerable to developing inflammation-associated colorectal carcinogenesis, to 4-nitroquinoline 1-oxide (4-NQO)-induced tongue carcinogenesis in order to clarify the role of inflammation in oral cancer. KAD (20 males and 22 females) and F344/NS1c (22 males and 23 females) rats received drinking water with or without 4-NQO (20 ppm) for eight weeks. Histopathological and immunohistochemical analyses of the tongue were performed at week 20. Additionally, the mRNA expression of inflammatory cytokines in the tongue mucosa was determined at week 8. Tongue squamous cell carcinoma (SCC) developed in the KAD and F344/NS1c rats that received 4-NQO. Regardless of gender, the incidence and multiplicity of tongue SCC were greater in the KAD rats than in the F344/NS1c rats. In addition, the multiplicity of tongue SCC in the female KAD rats was significantly greater than that observed in the male KAD (p < 0.01) and female F344/NS1c rats (p < 0.05). The levels of inflammation and the mRNA expression of inflammatory cytokines in the tongue in the 4-NQO-treated female KAD rats were the highest among the rats given 4-NQO. These results show that KAD rats, particularly females, are susceptible to 4-NQO-induced tongue carcinogenesis, suggesting the utility of models employing KAD rats for investigating the pathobiology of oral (tongue) carcinogenesis associated with inflammation.

Genetic expression signatures of oral submucous fibrosis and oral cancer-A preliminary microarray report

Background/purpose

Oral submucous fibrosis (OSF) is a potentially malignant disorder of oral squamous cell carcinoma (SCC). In this study, we obtained the genetic expression signatures of OSF and SCC by microarray analysis.

Materials and methods

Five patients with clinically evident OSF, five patients with SCC who also had existing OSF, and four normal volunteers who did not have a history of chewing betel quids were recruited. Biopsy specimens were obtained with an approved Institutional Review Board protocol. Total RNA from OSF or SCC was isolated and hybridized to a Human Oligo 1A (V2) Microarray (G4110B) chip against normal control RNA that was pooled from the four healthy volunteers.

Results

We found similar, but distinct genetic expression signatures for OSF and SCC. At the hierarchical clustering analysis, 24 known genes (23 upregulated and 1 downregulated) in OSF were differentially expressed consistently in all participants. Among the genes, XRCC5 was cloned and transfected into oral cancer GNM cells. The results demonstrated that the overexpression of XRCC5 increased the resistance of GNM cells to low-density X-ray irradiation and promoted the cell growth rate.

Conclusion

The distinct but similar genetic expression signatures seen in OSF and SCC suggested that this expression may be used as a supplemental diagnostic tool in pathology practice. This preliminary study showed that the XRCC5 gene promoted GNM cell growth and conferred resistance to low-density X-ray irradiation. Further studies on the effect of XRCC5 in oral cancer cells are in progress.

Efficacy of salvianolic acid B combined with triamcinolone acetonide in the treatment of oral submucous fibrosis

OBJECTIVE

The aim of this study was to investigate the effectiveness of triamcinolone acetonide (TA) and salvianolic acid B (SA-B) intralesional combined injection in the treatment of oral submucous fibrosis (OSF).

MATERIAL AND METHODS

A randomized clinical trial was performed. TA, SA-B, and TA combined with SA-B were consecutively applied intralesionally weekly for 20 weeks. Mouth opening and burning sensation improvement as determined by a 100-mm visual analog scale were evaluated at weeks 10, 20, and 44.

RESULTS

Forty-two subjects fulfilled the study without obvious adverse reactions. The net gain in mouth opening was 2.00 ± 1.21 mm in the TA group, 3.48 ± 2.23 mm in the SA-B group, and 5.50 ± 1.80 mm in the TA + SA-B group at week 44. The burning sensation improved by 3.05 ± 0.76 in the TA group, 4.96 ± 0.97 in the SA-B group, and 6.11 ± 0.93 in the TA + SA-B group by the end of the study.

CONCLUSIONS

TA + SA-B intralesional injections improved mouth open and burning sensation in these OSF patients.

Evaluation of PTEN immunoexpression in oral submucous fibrosis: role in pathogenesis and malignant transformation

Oral submucous fibrosis (OSMF) is a chronic debilitating disease and a premalignant condition of the oral cavity characterized by generalized submucosal fibrosis. Despite its precancerous nature, the molecular biology regarding its malignant potential has not been extensively studied. PTEN, a known tumor suppressor gene is mutated in a majority of human cancers and has also been implicated in several fibrotic disorders. The present study aims to evaluate the expression of PTEN in OSMF and oral squamous cell carcinoma (OSCC) and correlate it with the pathogenesis and malignant transformation of OSMF. 60 cases total of OSMF (30) and OSCC (30) were subjected to immunohistochemistry using PTEN antibody. Ten normal oral mucosa (NOM) specimens were also stained as controls. There was progressive loss of PTEN expression from normal mucosa to OSMF and OSCC (p ≤ 0.001). Significant differences were observed for PTEN expression between NOM and OSMF, OSMF and OSCC as well as NOM and OSCC. Though a progressive loss of PTEN was noticed between early OSMF and advanced OSMF, the variation did not reach statistical significance (p ≥ 0.001). Data suggest that there is a significant loss of PTEN expression in OSMF as compared to normal oral mucosa and that this trend increased from OSMF to OSCC. Thus, alteration of PTEN is likely an important molecular event in OSMF pathogenesis and oral carcinogenesis.

Areca nut in pathogenesis of oral submucous fibrosis: revisited

BACKGROUND

Oral submucous fibrosis is a disease due to a chronic, insidious change in fibro-elasticity, characterized by burning sensation in the oral cavity, blanching, and stiffening of the oral mucosa and oropharynx leading to trismus and inability to open the mouth. The symptoms and signs depend on the progression of the lesions and number of affected sites. It is predominantly seen in Indians and other Asians. Once the disease has developed, there is neither regression nor any effective treatment. It is considered as a pre-malignant stage of oral cancer, and the reported risk of malignant transformation varies from 2.3-7.6%.

CONCLUSIONS

The common etiological factor considered for this unremitting disease is use of areca nut; however, the precise mechanism still remains elusive and controversial. A wide range of treatment consisting of drugs, surgical therapy, and physiotherapy have been attempted till date, with varying degrees of benefit, but none of them have proved to be a cure for this disease. This field remains open for clinical trials and research. This paper aims to give an overview on the role of areca nut in the pathogenesis and malignant potential of oral submucous fibrosis.

Zinc and vitamin A can minimise the severity of oral submucous fibrosis

We report a case of a 24-year-old man who presented with a complaint of reduced mouth opening and a burning sensation. On examination, he was clinically diagnosed with oral submucous fibrosis (OSF). Following routine biopsy and histopathological confirmation of OSF, the patient was supplemented with zinc acetate along with vitamin A and was followed up for 4 months. Following treatment the patient reported increased mouth opening and a reduced burning sensation. Histopathologically re-epithelialisation was evident along with the appearance of normal rete pegs. The data for mouth opening, collagen content and epithelial thickness of six other cases similarly treated are also presented, showing a significant increase in mouth opening and epithelial thickness and decrease in collagen content. We propose the use of zinc acetate and vitamin A for the management of OSF.

Molecular genetics of premalignant oral lesions

Oral squamous cell carcinoma (OSCC) is characterized by cellular and subcellular alterations that are associated with a progression towards dedifferentiation and growth. There are several histologically distinct lesions of the oral cavity which have malignant potential. These are leukoplakia, erythroplakia, lichen planus, and submucous fibrosis. These are characterized by a spectrum of chromosomal, genetic, and molecular alterations that they share with each other as well as with the malignant lesions that develop from them. In this review we summarize the investigation of the molecular genetics of each of these lesions and relate them to the alterations, which have been demonstrated in OSCC, to define their location on the continuum of changes, which lead to malignant transformation.

A novel wavelet neural network based pathological stage detection technique for an oral precancerous condition

AIM

To describe a novel neural network based oral precancer (oral submucous fibrosis; OSF) stage detection method.

METHOD

The wavelet coefficients of transmission electron microscopy images of collagen fibres from normal oral submucosa and OSF tissues were used to choose the feature vector which, in turn, was used to train the artificial neural network.

RESULTS

The trained network was able to classify normal and oral precancer stages (less advanced and advanced) after obtaining the image as an input.

CONCLUSIONS

The results obtained from this proposed technique were promising and suggest that with further optimisation this method could be used to detect and stage OSF, and could be adapted for other conditions.