Microarray bioinformatic analysis
Analysis for microarray datasets was performed using R software. Filtering criterion was set to log fold change cutoff of 1.5 and adjusted P-value of 0.01 (Fig. 1). Twenty-two DE-miRNAs between cirrhotic HCV and HCC groups were generated, 4 miRNAs were upregulated and 18 were downregulated in HCC group (Log fold change and statistical significance are presented in supplementary table 1).
RNA sequencing bioinformatic analysis
MiRNAs differential expression analysis was conducted using false discovery rate (FDR) cutoff of 0.05, and fold change cutoff of 1 (Fig. 2). Nine significant DE-miRNAs were obtained, 3 were upregulated (miR-217, miR-224 and miR-183) and 6 were downregulated (miR-142, miR-199b, miR-150, miR-424, miR-215 and miR-3607) (Log fold change and FDR are shown in supplementary table 2).
Description of the study population
Demographic and clinical data records are summarized in Tables 1 and Fig. 3. No significant difference was observed in gender distribution between healthy control and HCC group (P = 0.5294), and between non-cirrhotic and cirrhotic groups (P = 0.1508). Moreover, no statistical difference was observed in age distribution among the healthy individuals, cirrhotic and HCC groups, excluding the non-cirrhotic group (P = 0.0662). Differences in serum levels of liver biomarkers; ALB, ALT, AST, T. Bil, D. Bil and AFP were statistically significant among the study groups.
Different indices as APRI, FIB-4 and AAR were used to assess the degree of fibrosis and cirrhosis in the study groups (Table 2, and Fig. 4). Significant fibrosis was calculated in 2.1%, 16.9% and 23.1% of non-cirrhotic, cirrhotic and HCC patients, respectively using APRI cutoff score > 1.5. However, applying FIB-4 cutoff score >3.27 predicated higher percentages of advanced fibrosis in 10.8%, 36%, and 49.2% of non-cirrhotic, cirrhotic and HCC patients, respectively. Moreover, AAR > 1 suggested the presence of cirrhosis in 75.4%, 73.8% and 84.3% of the three diseased groups, respectively. Results obtained from the non-invasive indices indicated the importance of combining different indices in addition to imaging techniques as US for precise determination of the degree of fibrosis and cirrhosis.
Tumor features and classification of patients among the different disease stages were assessed (Table 3). Patients were classified into Child A, B, and C in 69.7%, 24.2% and 6.1% of the cirrhotic patients, in addition to 78.3%, 20.3% and 1.4% of the HCC patients, respectively according to CTP score. While according to BCLC staging systems, the patients were classified into three groups: very early (stage 0; 17.9%), early (stage A; 64.2%), and intermediate stage (stage B; 17.9%). Furthermore, marked slight to moderate ascites was reported in 22.4% of the cirrhotic patients and 22.2% of the HCC patients. Single FL was diagnosed in 63.9% of the HCC patients, while 36.1% had multiple FLs. Additionally, 40.7% of the HCC patients has FL ≤ 3cm in diameter.
MiRNAs serum signature in the study groups
Fold changes of the DE-miRNAs among the study groups were represented in Fig. 5. The results of this study revealed that serum levels of the nine candidate miRNAs were differentially expressed in HCV and HCC patients in comparison to healthy individuals with high statistical significance (P-value < 0.0001) using Mann-Whitney U statistical test (Table 4). However, only miR-424 serum level showed statistical significance upon comparing HCV patients with those having HCC. The expression levels of miR-424, miR-199a, miR-142, and miR-224 were significantly altered in HCC patients compared to the non-cirrhotic subjects (P < 0.0001, P = 0.0001, P = 0.023, and P = 0.027, respectively). Whereas, miR-199a and miR-183 showed difference in differential expression between HCV cirrhotic and non-cirrhotic patients (P = 0.012 and P = 0.036, respectively) (Table 5).
Correlation between the studied miRNAs
Spearman’s correlation test was performed to investigate the correlation between the fold change of expression of each individual miRNA and the other miRNAs. Positive correlation was recorded between the expression of all miRNAs among the study groups, with high statistical significance (P < 0.0001) (Table 6). Moreover, the correlation between the miRNAs under study and some clinicopathological characteristics was performed. MiR-183, miR-199a and miR-215 were positively correlated with the age of the patients (P = 0.007, 0.037 and 0.026, respectively). While only miR-142 and miR-217 were positively correlated with gender (P = 0.036 and 0.001, respectively). Whereas, the whole panel of the nine miRNAs was positively correlated with the cirrhotic liver conditions and D. Bil (P < 0.0001), ALT and AST levels (P < 0.001). On the other hand, only miR-150 showed statistical significance negative correlation with T. Bil levels (P = 0.003) and with ALB levels for most of the targets (P < 0.001). Moreover, the association between the tumor characteristics and the miRNAs expression was investigated. Only miR-199a showed significant positive correlation with the AFP levels (P = 0.04). While for CTP score, miR-150 was negatively correlated (P = 0.009), while miR-217 and miR-3607 were positively correlated (P = 0.02, P = 0.032, respectively). Interestingly, no significant correlation was reported with BCLC staging.
Diagnostic potential of the DE-miRNAs in HCC patient compared to healthy individuals
Receiver operating characteristic (ROC) curves were plotted for the candidate miRNAs to discriminate HCC patients from healthy controls (Fig. 6 and Table 7). The Area under the curve (AUC) values were 0.993, 0.972, 0.968, 0.958, 0.957, 0.933, 0.928, 0.921, 0.868 corresponding to miR-424, miR-142, miR-199a, miR-215, miR-183, miR-217, miR-150, miR-224, and miR-3607, respectively with high statistical significance (P-value < 0.0001). All of the targets showed high sensitivity (ranging from 100% to 80.77%) and accuracy (ranging from 95.7% to 81.72%) for prediction of HCC patients. A combined panel of 5 miRNAs; where the whole panel is considered positive if 5 out of the 9 miRNAs tested positive, increased the sensitivity, specificity and accuracy of detection to 100%, 95.12%, and 97.85%, respectively (P-value < 0.0001).
Diagnostic potential of the DE-miRNAs in HCV patient compared to healthy individuals
To identify HCV patients from healthy individuals, ROC curves were drawn for the candidate miRNAs (Fig. 7 and Table 7). The AUC values were 0.941, 0.94, 0.927, 0.919, 0.913, 0.903, 0.882, 0.863, and 0.824 corresponding to miR-183, miR-424, miR-217, miR-199a, miR-215, miR-142, miR-150, miR-224, and miR-3607, respectively with high statistical significance (P-value < 0.0001). All of the targets showed high sensitivity (ranging from 91.58% to 80%) and accuracy (ranging from 90.44% to 79.41%) for discrimination of HCV patients. Combined panel of 5 miRNAs improved overall sensitivity, specificity and accuracy of detection to 90.53%, 85.37%, and 88.97%, respectively (P-value < 0.0001).
Diagnostic potential of the DE-miRNAs in HCC patient compared to non-HCC individuals
In a comparison between HCC patients with others without malignancy (healthy individuals, HCV non-cirrhotic and HCV cirrhotic patients), AUC were calculated and eight potential miRNAs had statistically significant values (Fig. 8 and Table 7). MiR-424, miR-199a, miR-150, miR-215, miR-224, miR-142, miR-183, and miR-3607 had AUC values of 761, 0.724, 0.706, 0.695, 0.691, 0.69, 0.664, and 0.664, respectively (P-value < 0.0001). Reasonable sensitivities (80.77% to 61.54%) and accuracies (65.96% to 57.98%) were recorded for the different targets. Using a combined panel of 5 miRNAs resulted in 80.77% sensitivity and 61.03% specificity for HCC detection (P -value < 0.0001).
Diagnostic potential of the DE-miRNAs in HCC (SVR / treatment naïve) patient compared to non-HCC (SVR / treatment naïve) patients
The overall ROC analysis measurements including AUC were improved after classifying the study groups in to SVR (Fig. 9 and Table 7) treatment naïve (Fig. 10 and Table 7). The highest AUC for both HCC (SVR) group HCC (treatment naïve) group was recorded for miR-424 (0.8, and 0.835, respectively) (P-value < 0.0001). Similarly, 5-miRNAs combined panel increased the overall sensitivity, specificity and accuracy for HCC (SVR) patients’ prognosis to (83.33%, 63.73% and 67.46%, respectively). While combining 6 miRNAs in one panel, improved the calculated measurements in HCC (treatment naïve patients) (sensitivity 89.29%, specificity 72.6% and accuracy 77.23%).
Diagnostic potential of the DE-miRNAs in HCC patients compared to patients with HCV
In order to develop potential biomarker to differentiate HCC patients from HCV subjects, ROC analysis was performed and resulted in three statistically significant targets; miR-424, miR-199a, and miR-150, with P-values 0.001, 0.018, and 0.028, respectively (Fig. 11 and Table 7). The highest calculations were obtained for miR-424. Comparison between miRNA-424 and AFP (the current HCC serum biomarker) resulted in comparable sensitivities, 63.46% for the former and 62.32% for the later. Although AFP specificity and accuracy (64.57% and 63.78%) were better than those for miR-424 (57.9% and 59.86%). However, the choice of a combined panel of 2 miRNAs with or without AFP didn’t provide significant improvement in the ROC analysis measurements.
Diagnostic potential of the DE-miRNAs in HCC (SVR) patients compared to patients with HCV (SVR)
Similarly, ROC curves were constructed to determine the best AUC for patients with HCC (SVR) compared to HCV (SVR) (Fig. 12, and Table 7). Three miRNAs had statistically significant results (miR-424, miR142, and miR-3607) with P-values 0.01, 0.018, and 0.014, respectively. The ROC measurements obtained (sensitivities: 66.67%, 66.67%, and 70.83%, accuracies: 62.1%, 68.97%, 58.62%, respectively) were remarkably higher than sensitivity and accuracy recorded for AFP (51.43% and 58.1%, respectively). Using combined panel of 2 miRNAs enhanced the sensitivity, specificity and accuracy of detection (70.83%, 61.9%, and 64.37%; respectively). Addition of AFP biomarker to the combined panel improved the overall sensitivity (70.83%), specificity (73%) and accuracy (72.4%). However, ROC analysis to discriminate patients with HCC (treatment naïve) from HCV (treatment naïve) patients didn’t show any statistically significant AUC for any of the targets.