Investigation of methylation and expression levels of Glycophorin C (GYPC) gene in oral squamous cell carcinoma.

Oral squamous cell carcinoma (OSCC) is the most common type of oral cancer and the ethiological factors such as alcohol and tobacco comsumption, geographical region, poor oral hygiene affect the incidence and mortality rates of this disease. In the TUBITAK-SBAG-114S497 project completed by Semra Demokan et al., According to bioinformatics analysis of methylation and expression array results, cpg islets of the Glycophorin (GYPC) gene were methylated and expression levels were decreased in tumor and conjugated normal tissues of OSCC patients. GYPC encodes the GPC and GPD proteins that can be integrated into the membrane in erythrocytes and provides membrane stability of red blood cells. DNA hypermethylation plays an important role in erythrocytes and carcinogenesis as a result of suppressing gene expression in cancer development. In this study, we investigated the potential of methylation status in the GYPC gene as a biomarker for early diagnosis and prognosis in OSCC. In our study, tissue and serum samples of 50 patients diagnosed with OSCC and 10 healthy individuals were examined in order to investigate methylation and expression status by QMSP and QRT-PCR methods, respectively. Methylation and expression levels of GYPC gene was observed 48% (24/50) of the patients, separately. Methylation-based expression decrease observed in 12 of 24 patients who had methylation in tumor tissue. Statistically significant difference was found between GYPC expression decrease with metastasis (p=0,006) and methylation with lymph node involvement (p=0.011) and metastasis (p=0,044). In addition, significant differences found with methylation-based expression levels and smoking (p=0,019), metastasis (p=0,019), alcohol consumption (p=0,031). Key Words: methylation, gene expression, epigenetic biomarker, oral squamous cell carcinoma, GYPC gene The present work was supported by the Research Fund of Istanbul University. Project No. TYL-2018-32628