OBJECTIVE: To explore the feasibility of using cyclin D1 as a prognostic marker in tongue and cheek SCC by the fluorescent-in-situ hybridization (FISH) method.
METHODS: Fifty paraffin-embedded samples (25 each of cheek and tongue SCCs) were obtained from the archives of the Oral Pathology Diagnostic Laboratory. Sociodemographic data, histopathologic diagnoses, lymph node status and survival data were obtained from the Malaysian Oral Cancer Database and Tissue Bank System (MOCDTBS)coordinated by the Oral Cancer Research and Coordinating Centre (OCRCC), University of Malaya. The FISH technique was used to detect the amplification of cyclin D1 using the Vysis protocol. Statistical correlations of cyclin D1 with site and lymph node status were analyzed using the Fisher exact test. Kaplan-Meier and Log Rank (Mantel-Cox) test were used to analyze cyclin D1 amplification and median survival time.
RESULTS: Positive amplification of cyclin D1 was detected in 72% (36) of OSCCs. Detection of positive amplification for cyclin D1 was observed in 88% (22) and 56% (14) of the tongue and cheek tumors, respectively, where the difference was statistically significant (P=0.012). Lymph node metastasis of cheek SCCs showed a trend towards a significant association (P= 0.098) with cyclin D1 amplification whereas the lymph node metastasis of tongue SCC was clearly not significant (P=0.593).There was a statistically significant correlation between cyclin D1 positivity and survival rate (P=0.009) for overall SCC cases and (P<0.001) for cheek SCC cases.
CONCLUSION: The present study found that cyclin D1 amplification may differ in different subsites of OSCC (tongue vs cheek) and its positive amplification implies an overall poor survival in OSCCs, particularly those arising in cheeks.
OBJECTIVES: The objectives of this study were to investigate the CELSR3 hypermethylation level in oral squamous cell carcinomas (OSCCs) using methylation-sensitive high-resolution melting analysis (MS-HRM) and to correlate CELSR3 methylation with patient demographic and clinicopathological parameters.
MATERIALS AND METHODS: Frozen tissue samples of healthy subjects' normal mucosa and OSCCs were examined with regard to their methylation levels of the CELSR3 gene using MS-HRM.
RESULTS: MS-HRM analysis revealed a high methylation level of CELSR3 in 86% of OSCC cases. Significant correlations were found between CELSR3 quantitative methylation levels with patient ethnicity (P=0.005), age (P=0.024) and pathological stages (P=0.004). A moderate positive correlation between CELSR3 and patient age was also evident (R=0.444, P=0.001).
CONCLUSIONS: CELSR3 promoter hypermethylation may be an important mechanism involved in oral carcinogenesis. It may thus be used as a biomarker in OSCC prognostication.
METHODS: The expression of IFITM3 in OSCC and normal oral mucosal tissues was assessed by qRT-PCR and immunohistochemistry. The role of IFITM3 in driving OSCC cell proliferation and survival was examined using siRNA-mediated gene knockdown, and the role of IFITM3 in driving cell cycle regulators was examined using Western blotting.
RESULTS: We found that IFITM3 is overexpressed in more than 79% of primary OSCCs. We also found that IFITM3 knockdown led to impaired OSCC cell growth through inhibition of cell proliferation, induction of cell cycle arrest, senescence and apoptosis. In addition, we found that IFITM3 knockdown led to reduced expressions of CCND1 and CDK4 and reduced RB phosphorylation, leading to inhibition of OSCC cell growth. This information may be instrumental for the design of novel targeted therapeutic strategies.
CONCLUSIONS: From our data we conclude that IFITM3 is overexpressed in OSCC and may regulate the CCND1-CDK4/6-pRB axis to mediate OSCC cell growth.
MATERIALS AND METHODS: In mutation screening of CRNN gene, gDNA from OSCC tissues were extracted, amplified, and followed by direct sequencing. OSCC samples were also subjected to fragment analysis on CRNN gene to investigate its microsatellite instability (MSI) and loss of heterozygosity (LOH). Immunohistochemistry was performed to validate CRNN downregulation in OSCC samples.
RESULTS: No pathogenic mutation was found in CRNN gene, while high frequency of allelic imbalances was found at 1q21.3 region. MSI was found more frequent (25.3 %) than LOH (9.3 %). Approximately 22.6 % of cases had high MSI which reflects higher probability of inactivation of DNA mismatch repair genes. MSI showed significant association with no betel quid chewing (p = 0.003) and tongue subsite (p = 0.026). LOH was associated with ethnicity (p = 0.008) and advanced staging (p = 0.039). The LOH at 1q21.3 was identified to be as an independent prognostic marker in OSCC (HRR = 7.15 (95 % CI, 1.41-36.25), p = 0.018). Downregulation of CRNN was found among MSI-positive OSCCs and was associated with poor prognosis (p = 0.044).
CONCLUSION: This study showed a significant correlation between LOH/MSI at 1q21.3 with clinical outcomes and that downregulation of CRNN gene could be considered as a prognostic marker of OSCC.
CLINICAL RELEVANCE: Insights of the downregulation mode of CRNN gene lays the basis of drug development on this gene as well as revealing its prognostic value.