Differential Expression of MRPS18 Family Genes in Brain Tumor Samples.

Abstract

Background: Brain tumors account for 2%-3% of all malignant neoplasms and 85%-90% of all primary tumors of the central nervous system with the 5-year survival rate of 35%. Additional biomarkers could help refine the molecular profile of brain tumors and prognosis of the disease.

Aim: To study differential expression patterns of the MRPS18 family genes in tumor tissue and the peripheral blood of patients with brain tumors of various types.

Materials and methods: The total RNA was isolated from blood and tumor tissue samples of 27 patients with brain tumors. The quantitative polymerase chain reaction (qPCR) was performed. Also, immunohistochemical (IHC) studies of the MRPS18 family proteins were performed on deparaffinized tissue sections.

Results: The MRPS18-1-3 genes were highly expressed at the mRNA level in tumor tissue and the peripheral blood of patients with brain tumors. All 3 genes showed different patterns of expression depending on the tumor type. The highest MRPS18-1 mRNA expression was detected in glioblastoma (GB) samples in both tumor samples and the peripheral blood. In general, MRPS18-1 expression was higher in G4 tumors, compared to G2. MRPS18-3 gene was expressed as higher levels in G2 samples and in embryonic tumors. MRPS18-2 was expressed in all studied samples, with no regard to the tumor grade or type. The MRPS18-2 IHC staining was detected at high levels in most brain tumors.

Conclusions: The MRPS18 family genes showed similar patterns of mRNA expression in tissue samples of brain tumors and peripheral blood of patients. The highest levels of MRPS18-1 mRNA were detected in GB samples, while the highest protein signal was detected for MRPS18-2 in almost all brain tumor samples.