Prognostic significance of microvascular invasion and related microRNAs after hepatic resection for hepatocellular carcinoma

다국어 초록 (Multilingual Abstract)

Prognostic significance of microvascular invasion in tumor stage for hepatocellular carcinoma
Background: The presence of microvascular invasion (McVI) in hepatocellular carcinoma (HCC) has been proposed as a cause of recurrence and poor survival, although this has not been officially emphasized in staging systems. Thus, we conducted a retrospective study to investigate the prognostic importance of McVI in tumor staging in patients with HCC who underwent hepatic resection. Patients and Methods: A retrospective analysis was performed of patients who underwent hepatic resection for HCC at our center from 1994 to 2012. Patients with HCC were classified into four groups based on the presence of McVI and extent of gross vascular invasion (VI). Results: The 5-years overall and recurrence-free survival rates of 676 patients were 63.3% and 42.6%, respectively. There was no difference in tumor recurrence or survival rate between patients with HCC and McVI without gross VI and those with gross VI confined to segmental/sectional branches. Multivariate analysis revealed that the extent of VI based on the presence of McVI and gross VI was independently associated with tumor recurrence and overall survival. Conclusions: McVI was revealed to be an important risk factor similar to gross VI confined to a segmental/sectional branch in patients with HCC who underwent hepatic resection. This finding should be considered when estimating the stage for prognosis.

Conditional survival analysis demonstrates that recurrence risk of surgically treated hepatocellular carcinoma evolves with time
Objective: The study aim was to investigate long-term change in tumor recurrence risk in patients with hepatocellular carcinoma (HCC) after hepatic resection. Recurrence probability over time was estimated by conditional survival (CS) analysis. Patients and Methods: Early-stage HCC patients with hepatic resection were selected for inclusion from our surgery database. Variables predictive of tumor recurrence were identified by univariate and multivariate analyses. Five-year recurrence-free CS probability was calculated for all patients and for risk groups stratified by independent predictors. Results: In this series of 436 patients, tumor size >5 cm, microvascular invasion, positive resection margin, liver cirrhosis, and a indocyanine green retention ratio at 15 minutes (ICG-R15) >20% were independently predictive of tumor recurrence. The estimated 5-year recurrence-free CS probability improved with each additional year of recurrence-free survival, and the improvement was significantly greater in the high risk than in the low or intermediate risk groups. Conclusion: CS provides added value during follow-up of early-stage HCC patients treated by surgical resection.

MicroRNA-9 overexpression is associated with microvascular invasion and poor survival after hepatic resection for hepatocellular carcinoma
Purpose: Although microvascular invasion (McVI) has prognostic value for patients with hepatocellular carcinoma (HCC) who have undergone hepatic resection, few studies have investigated the relationship between McVI and the aberrant expression of microRNAs. This study identified microRNAs selectively expressed in HCC with McVI and investigated their prognostic roles. Patients and methods: Clinical data and microRNA expression profiles for 355 HCC patients were extracted from The Cancer Genome Atlas database. MicroRNAs that were differentially expressed in the patients with McVI and those without vascular invasion were identified and investigated as potential prognostic factors for HCC. Results: MicroRNA-9-5p was upregulated more (fold change [FC] 2.30; false discovery rate [FDR] < 0.001) and microRNA-675-5p was downregulated more (FC 0.52; FDR = 0.005) in the patients with McVI. Multivariate analysis revealed that the types of surgery (HR 1.718, 95% CI 1.169–2.524, P = 0.006), the presence of a residual tumor (HR 3.475, 95% CI 1.507–8.013, P = 0.003) and advanced TNM stage (HR 1.817, 95% CI 1.163–2.839, P = 0.009) were independently associated with tumor recurrence, and that advanced TNM stage and overexpression of microRNA-9 were independent risk factors for overall survival after hepatic resection for HCC (HR 1.671, 95% CI 1.114–2.508, P = 0.013 and HR 3.451, 95% CI 1.796–6.630, P < 0.001, respectively). Conclusion: Overexpression of microRNA-9-5p was associated with McVI and poor survival of patients after hepatic resection for HCC.

목차 (Table of Contents)

• 1) List of Text
• I. Introduction ‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧ 1
• II. Prognostic significance of microvascular invasion in tumor stage for hepatocellular carcinoma ‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧ 3
• III. Conditional survival analysis demonstrates that recurrence risk of surgically treated hepatocellular carcinoma evolves with time ‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧ 27
• IV. MicroRNA-9 overexpression is associated with microvascular invasion and poor survival after hepatic resection for hepatocellular carcinoma: an analysis using The Cancer Genome Atlas database ‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧ 45
• V. Appendix
• A. Bibliography ‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧ 64
• B. List of scientific papers included in the thesis ‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧ 77
• 2) List of Figures
• II. Prognostic significance of microvascular invasion in tumor stage for hepatocellular carcinoma
• Figure 1. Flow diagram shows the selection of patients who were eligible for this study. ‧‧‧‧‧‧‧‧‧‧‧‧‧ 7
• Figure 2. Comparison of (a) recurrence-free and (b) overall survival of patients stratified into groups A–D. ‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧ 14
• Figure 3. Summary of statistically significant clinicopathological factors on (a) recurrence-free survival and (b) overall survival using the Cox regression proportional hazards model. ‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧ 22
• III. Conditional survival analysis demonstrates that recurrence risk of surgically treated hepatocellular carcinoma evolves with time
• Figure 4. Flow diagram showing the selection of patients who were eligible for this study. ‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧ 31
• Figure 5. Cumulative recurrence-free and overall survival of the 436 patients with resected early-stage HCC estimated by the Kaplan–Meier method. ‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧ 33
• Figure 6. Five-year recurrence-free conditional survival (CS) at each additional year after hepatic resection. ‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧ 35
• Figure 7. Recurrence-free survival curves (a) and five-year recurrence-free CS probability (b) in three risk groups. ‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧ 38
• Figure 8. Five-year recurrence-free CS probability with (a) tumor size less than or greater than 5 cm, (b) ICG-R15 values less than or more than 20% (c) presence or absence of microvascular invasion, and (d) presence or absence of background liver cirrhosis. ‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧ 40
• IV. MicroRNA-9 overexpression is associated with microvascular invasion and poor survival after hepatic resection for hepatocellular carcinoma: an analysis using The Cancer Genome Atlas database
• Figure 9. Study flowchart. McVI, microvascular invasion; HCC, hepatocellular carcinoma; DESeq., differentially expressed sequences ‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧ 47
• Figure 10. Comparison of (a) recurrence-free survival and (b) overall survival of patients between patients with microvascular invasion [McVI (+), Group B] and without vascular invasion [McVI (−), Group A].; NS, not significant ‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧ 52
• Figure 2. Comparison of (a) recurrence-free survival and (b) overall survival curves between over and under microRNA-9 expression ‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧ 59
• 3) List of Tables
• II. Prognostic significance of microvascular invasion in tumor stage for hepatocellular carcinoma
• Table 1. Comparison of clinicopathological data for patients classified into four groups. ‧‧‧‧‧‧‧‧‧‧‧‧‧ 9
• Table 2. Univariate analysis of factors predictive of recurrence-free and overall survival. ‧‧‧‧‧‧‧‧‧ 16
• III. Conditional survival analysis demonstrates that recurrence risk of surgically treated hepatocellular carcinoma evolves with time
• Table 3. Univariate and multivariate analysis to identify prognostic factors associated with tumor recurrence. ‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧ 36
• IV. MicroRNA-9 overexpression is associated with microvascular invasion and poor survival after hepatic resection for hepatocellular carcinoma: an analysis using The Cancer Genome Atlas database
• Table 4. Comparison of clinicopathological data of hepatocellular carcinoma patients with no vascular invasion (Group A) or with microvascular invasion (Group B) ‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧ 50
• Table 5. Univariate analysis of factors predictive of recurrence-free survival and overall survival ‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧ 55