Differentiation of high-grade gliomas (WHO grades III and IV) is still a pressing issue despite advances of molecular biology in tumor stratification. Even with a comprehensive approach to differential diagnosis, uncertainty sometimes arises in classifying a glioma into a particular grade. This can complicate prognosis and selection of appropriate treatment. Objective. To develop an effective method for differentiating high-grade gliomas based on marker gene expression analysis. Material and methods. We analyzed expression of 31 marker genes in high-grade glioma samples (Grade III and IV) diagnosed with isocitrate dehydrogenase (IDH)-mutated oligodendroglioma, IDH-mutated astrocytoma and IDH-wildtype glioblastoma. Real-time polymerase chain reaction was used. Spearman rank correlation method was applied to select genes whose expression was most closely related to glioma grade. Gene expression and their ratios were compared in groups of Grade III and IV malignant gliomas using the Mann-Whitney test. Results. Expression ratios of three genes (CD44, CIRBP, and SOX2) were selected to assess malignancy grade. Expression ratios for these genes distinguishes IDH wild-type glioblastomas from IDH-mutated astrocytomas and oligodendrogliomas. They also have a stronger correlation with glioma grade than expression of each individual marker gene. Conclusion. Original method based on marker gene expression ratios does not replace standard diagnostic protocols, but may be an additional tool for optimized diagnostic process. This approach will be valuable to minimize errors and personalize therapeutic strategies. The last one is critical for prognosis.
Drozd et al. (Tue,) studied this question.