MRTO4 acts as an independent prognostic and immunological biomarker and is correlated with tumor microenvironment in hepatocellular carcinoma.

Liver cancer is a malignant tumor found worldwide. mRNA turnover 4 homolog (MRTO4) is highly expressed in hepatocellular carcinoma (HCC) tissues, and we explored its relationship with HCC. All cancer data were downloaded from the Cancer Genome Atlas (TCGA), the Cancer Immune Atlas (TCIA), and the Human Protein Atlas (THPA). Stromal scores, immune scores, and ESTIMATE scores were calculated by "ESTIMATE" R package. Single sample gene set enrichment analysis and CIBERSORT were used to evaluate the immune status and infiltration of cancer tissues. pRRophetic R package was used to predict the half-maximal inhibitory concentration (IC50) of different drugs in each sample. MRTO4 overexpression was associated with poor prognosis in HCC, and positively correlated with the stage and grade of HCC patients. The average immunophenoscore (IPS) of the low MRTO4 group was significantly higher than that of the high MRTO4 group. Tumor microenvironment (TME) scores were significantly higher in the low MRTO4 group than in the high MRTO4 group in HCC. MRTO4 expression was positively correlated with tumor mutation burden (TMB) and was positively correlated with most immune checkpoint gene expressions in HCC. Drug sensitivity analysis showed significantly higher IC50 values for 5-fluorouracil, gemcitabine, and sorafenib in patients with low MRTO4 expression than in those with high MRTO4 expression. MRTO4 acts as an independent prognostic and immunological biomarker and is correlated with clinical stage, tumor grade, and drug sensitivity in HCC. It may serve as a putative therapeutic target and potential biomarker for prognosis of HCC.