Expression of Radioresistant Gene PEG10 in OSCC Patients and Its Prognostic Significance

Abstract

<br /> <strong><span style="font-size: small;">Background: </span></strong><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">Oral squamous cell carcinoma (OSCC) is one of the most common forms of cancer occurring worldwide. PEG10 is well known as a paternally expressed gene from a newly recognized imprinted region at human </span></span><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">chromosome 7q21. Previous study had demonstrated that the significant expression of PEG10 was found in radioresistant OSCC cell line and its expression was significantly associated with poor survival in several cancers. Therefore it has </span></span><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">been evaluated as a potential marker in OSCC patients undergoing radiotherapy. </span></span><strong><span style="font-size: small;">Objective: </span></strong><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">This study was conducted </span></span><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">to analyze the mRNA expression of PEG10 in OSCC and its expression in relation to clinicpathological features, radiotherapy treatment response and survival. </span></span><strong><span style="font-size: small;">Methods: </span></strong><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">This study included tissue specimens obtained via biopsy of </span></span><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">118 patients with OSCC who were recommended for radiotherapy treatment and 80 healthy control tissues analysis of mRNA expression of PEG10 was done by real-time quantitative reverse transcriptase-polymerase chain reaction </span></span><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">(qRT-PCR). Patients were treated with 70 Gy of radiation dose by shrinking field technique using Cobalt-60 teletherapy </span></span><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">machine. </span></span><strong><span style="font-size: small;">Results: </span></strong><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">Significantly higher mRNA expression of PEG10 was found in OSCC patients when compared with matched controls. High level of PEG10 mRNA expression showed a significant correlation with lymph node metastasis </span></span><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">(</span></span><em><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">p </span></span></em><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">= 0.0047) and tumor stage (</span></span><em><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">p </span></span></em><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">= 0.0499). Multivariate Cox regression analysis revealed that high level of mRNA </span></span><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">expression of PEG10 was significantly associated with poor survival (</span></span><em><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">p </span></span></em><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">< 0.05). Our research demonstrated that the expression of PEG10 was higher in radioresistant tumor. </span></span><strong><span style="font-size: small;">Conclusion: </span></strong><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">We observed significantly increased expression of PEG10 in context of lymph node status, advanced stage and poor survival in our study. Thus PEG10 gene can be </span></span><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">used as potential predictive and prognostic biomarker in OSCC patients undergoing radiotherapy. </span></span>