Expression of Connexin 43 (Cx43) in Oral Submucous Fibrosis and Its Malignant Transformation to Oral Squamous Cell Carcinoma

Mugundan, R N (2019) Expression of Connexin 43 (Cx43) in Oral Submucous Fibrosis and Its Malignant Transformation to Oral Squamous Cell Carcinoma. Masters thesis, Ragas Dental College and Hospital, Chennai.


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BACKGROUND: Head and neck cancers are the 11th most common malignancy worldwide. Oral squamous cell carcinoma (OSCC) can occur in various parts of the oral cavity like the buccal mucosa, gingiva, tongue and the palate. The tumor has a high mortality as a result of its high invasiveness and metastatic capacity. The OSCCs are usually preceded by premalignant lesions which are now referred to as Oral Potentially Malignant Disorders (OPMD) by World Health Organization (WHO). Since not all of the OPMDs progressed to malignancy. Features of epithelial dysplasia are seen in advanced OSF and could lead to their malignant transformation. Cellular cohesion is maintained by Gap junctions that connects the cytoplasm of one adjacent cell to the other, Connexins are gap junction proteins that are expressed throughput the epithelium. Among them Connexin 43 (Cx43) is seen expressed extensively thoughout the tissues. Various studies have described the reduced expression of Cx43 in premalignant lesions and in carcinomas. There are no studies in the literature that had analyzed the Cx43 in oral submucous fibrosis and in its malignant transformation to oral squamous cell carcinoma. AIM OF THE STUDY: To evaluate the expression of Connexin 43 (Cx43), in formalin fixed paraffin embedded tissues of normal mucosa, oral submucous fibrosis (OSF), epithelial dysplasia and OSCC with history of OSF through immunohistochemistry. MATERIALS AND METHODS: In this study, we had a total of 39 cases (N=29) categorized into group I (normal mucosa), group II (OSF) (n=14), group III (n=12) and group IV (OSCC with history of OSF) (n=7). Immunohistochemistry was performed using Connexin43 (Cx43) Monoclonal antibody (Thermofisher ScientificTM). The staining intensity between the basal cell layer, suprabasal cell layer and the connective issue were observed and compared with each other. The staining intensity was graded as mild, moderate and intense. The descriptives were analysed using SPSS software (Version 21). p- value < 0.05 was considered statistically significant. RESULTS: The Cx43 expression in group I (Normal mucosa), 6 (100%) of the cases showed expression of Cx43 in the basal cell layer, in group II (OSF), 10 (64.3%) cases and in group III (epithelial dysplasia) 12 (100%) cases had no expression of Cx43. group IV, 7 (100%) cases showed lack of Cx43 expression in the basal cell layer. The suprabasal cell layer showed postivity for Cx43 expression and was predominant. Group I showed 5 (83.3%) cases that had mild expression, while group II demonstrated mild expression of Cx43 in 7 (50%) cases. In group III, 4 (33.3%) had a mild expression and 3 (35%) had a moderate expression for Cx43. Group IV had (71.4%) cases that were negative for Cx43 expression. The staining intensity between the groups were statistically significant (p = 0.033) All the groups stained positive for Cx43, while 1 (14.3%) cases showed a severe expression. On comparing group II (OSF) and group IV(OSCC with OSF). There was an increased expression of Cx43 in the suprabasal cell layer of 12 (85.7%) cases in group II when compared with group III and group IV. This finding was statistically significant (p=0.046). CONCLUSION: There was a reduced expression of Cx43 in cases of epithelial dysplasia and OSCC with history of OSF. However, further studies are required with a larger sample size to further validate the finding that reduced Cx43 expression of Cx43 could be an early event in oral carcinogenesis.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Connexin43, Oral submucous fibrosis, Oral squamous cell carcinoma, Epithelial dysplasia, Gap junction, GJIC.
Subjects: DENTAL > Oral Pathology and Microbiology
Depositing User: Subramani R
Date Deposited: 12 Aug 2019 15:19
Last Modified: 12 Aug 2019 15:19

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