Context: Results from recent molecular epidemiologic studies suggest that the timeless genes play a role in tumorigenesis, possibly by influencing cell cycle or other pathways relevant to cancer.
Aims: The aim of this study was to explore the expression level of the timeless gene in human glioma.
Subjects and methods: Using immunohistochemical staining, methylation-specific polymerase chain reaction techniques, we examined the expression of the timeless gene in 94 gliomas.
Statistical analysis used: The association between tumor grade and expression of the investigated proteins was assessed using the Spearman, Chi-square test, and two-sample t-test, included in the Statistical Package for the Social Science, version 13.0.
Results: The expression levels of timeless mRNA in high-grade glioma were significantly different from the surrounding nontumor tissues (P < 0.01). The difference in the expression of timeless in low-grade gliomas and the surrounding nonglioma tissues was insignificant (P > 0.05). The intensity of immunoactivity for TIMELESS in high-grade gliomas was significantly higher than that of low-grade gliomas (r = -0.403, P = 0.012 < 0.05), nontumor tissues around high-grade gliomas (r = -0.376, P = 0.027 < 0.05), whereas there was no difference in the intensity of immunoactivity for TIMELESS between low-grade gliomas and the surrounding nontumor tissues (P > 0.05).
Conclusions: The expression of timeless in high-grade gliomas was significantly higher than that of the low-grade gliomas and nonglioma. Therefore, we suggest that disturbances in timeless expression may result in the disruption of the control of normal circadian rhythm, thus benefiting the survival of glioma cells and promoting carcinogenesis.
Keywords: Carcinogenesis; glioma; timeless.