Significantly different expression levels of microRNAs associated with vascular invasion in hepatocellular carcinoma and their prognostic significance after surgical resection

Abstract

Background: Although gross vascular invasion (VI) has prognostic significance in patients with hepatocellular carcinoma (HCC) who have undergone hepatic resection, few studies have investigated the relationship between gross VI and aberrant expression of microribonucleic acids (miRNAs and miRs). Thus, the objective of this study was to identify miRNAs selectively expressed in HCC with gross VI and investigate their prognostic significance.

Materials and methods: Eligible two datasets (accession number: GSE20594 and GSE67140) were collected from the National Center for Biotechnology Information's (NCBI) Gene Expression Omnibus (GEO) database to compare miRNAs expression between HCC with and without gross VI. Differentially expressed miRNAs were externally validated using expression data from The Cancer Genome Atlas (TCGA) database. Prognostic significance and predicted functions of selected miRNAs for HCC were also investigated.

Results: Thirty-five miRNAs were differentially expressed between HCC with and without gross VI in both datasets. Among them, three miRNAs were validated using TCGA database. miR-99a, miR-100, and miR-148a were downregulated to a greater extent in patients with HCC and gross VI than in those with HCC but no gross VI. Receiver operating characteristic (ROC) curve analysis showed discriminatory power of these miRNAs in predicting gross VI. Multivariate survival analysis revealed that types of surgery, advanced tumor node metastasis (TNM) stage, and low expression of miR-100-5p were independently associated with tumor recurrence. It also revealed that types of surgery, advanced TNM stage, low expression of miR-100-5p and miR-148a-3p were independent risk factors for overall survival (OS) after hepatic resection for HCC. A text mining analysis revealed that these miRNAs were linked to multifaceted hallmarks of cancer, including "invasion and metastasis."

Conclusions: Low expressions of miR-100-5p and miR-148a-3p were associated with gross VI and poor survival of patients after hepatic resection for HCC.

Fig 1

(a) Study flowchart, (b) Thirty-five differentially expressed miRNAs in gross VI group compared to negative VI group in both GSE20594 and GSE67140. CHAT, Cancer Hallmarks Analytics Tool; TCGA LIHC, The Cancer Genome Atlas Liver Hepatocellular Carcinoma; VI, vascular invasion.

Fig 2

(a) Expression difference of four miRNAs according to vascular invasion status, and (b) ROC curves of these miRNAs distinguishing HCC tissues on the basis of the absence or presence of gross VI (miR-99a-5p, miR-100-5p, and miR-148a-3p). FDR, false discovery rate.

Fig 3. Summary of statistically significant factors on tumor recurrence and overall survival using Cox regression proportional hazards model.

TNM, American Joint Committee on Cancer Tumor Node Metastasis; HR, hazard ratio; CI, confidence interval.

Fig 4. GO functional annotation for significantly related targets of selected miRNAs (miR-99a-5p, miR-100-5p and miR-148a-3p).

BP, biological process; CC, cellular component; MF, molecular function.

Fig 5

(a) Venn diagram demonstrating the overlap between differential mRNAs screened by GSE16571 dataset and miR-100-5p targets from MiRWalk2.0 database, and (b) Scatter plot showing significantly negative correlation between miR-100-5p and mRNA expression levels of ACLS3 and CTDSPL. (c) Summary of CHAT analysis for miR-99a, miR-100, and miR-148a. RPM, reads per million.