Molecular evolution in different subtypes of multifocal hepatocellular carcinoma

BACKGROUND

Multifocal hepatocellular carcinoma (MF-HCC) accounts for > 40% of HCCs, exhibiting a poor prognosis than single primary HCCs. Characterizing molecular features including dynamic changes of mutational signature along with clonal evolution, intrahepatic metastatic timing, and genetic footprint in the preneoplastic stage underlying different subtypes of MF-HCC are important for understanding their molecular evolution and developing a precision management strategy.

METHODS

We conducted whole-exome sequencing in 74 tumor samples from spatially distinct regions in 35 resected lesions and adjacent noncancerous tissues from 11 patients, 15 histologically confirmed preneoplastic lesions, and six samples from peripheral blood mononuclear cells. A previously published MF-HCC cohort (n = 9) was included as an independent validation dataset. We combined well-established approaches to investigate tumor heterogeneity, intrahepatic metastatic timing, and molecular footprints in different subtypes of MF-HCCs.

RESULTS

We classified MF-HCCs patients into three subtypes, including intrahepatic metastasis, multicentric occurrence, and mixed intrahepatic metastasis and multicentric occurrence. The dynamic changes in mutational signatures between tumor subclonal expansions demonstrated varied etiologies (e.g., aristolochic acid exposure) underlying the clonal progression in different MF-HCC subtypes. Furthermore, the clonal evolution in intrahepatic metastasis exhibited an early metastatic seeding at 10-4-0.01 cm3 in primary tumor volume (below the limits of clinical detection), further validated in an independent cohort. In addition, mutational footprints in the preneoplastic lesions for multicentric occurrence patients revealed common preneoplastic arising clones, evidently being ancestors of different tumor lesions.

CONCLUSION

Our study comprehensively characterized the varied tumor clonal evolutionary history underlying different subtypes of MF-HCC and provided important implications for optimizing personalized clinical management for MF-HCC.

Outcomes of Salvage Liver Transplantation and Re-resection/Radiofrequency Ablation for Intrahepatic Recurrent Hepatocellular Carcinoma: A New Surgical Strategy Based on Recurrence Pattern

BACKGROUND

The treatment of intrahepatic recurrent hepatocellular carcinoma (HCC) has been poorly investigated, and the optimal treatment strategy remains unclear.

AIMS

The aim of this study was to compare outcomes between salvage liver transplantation (SLT) and re-resection (RR)/radiofrequency ablation (RFA) for intrahepatic recurrent HCC according to recurrence pattern.

METHODS

Based on postoperative histopathological examination, 122 patients with intrahepatic recurrent HCC were divided into an intrahepatic metastasis (IM, n = 75) group and a multicentric occurrence (MO, n = 47) group. The demographic, clinical, and primary and recurrent tumor characteristics of the IM group and the MO group were collected and compared. Overall survival (OS) and disease-free survival (DFS) were analyzed, and subgroup analysis according to retreatment type (SLT vs. RR/RFA) was conducted. Twenty-nine clinicopathological variables potentially related to prognostic factors affecting survival were analyzed using a Cox proportional hazard model.

RESULTS

The patients that received SLT treatment exhibited favorable DFS compared to patients that received RR/RFA (P = 0.002). OS (P < 0.001) and DFS (P = 0.008) rates were significantly increased in the MO group compared with in the IM group. Subgroup analysis revealed that DFS was significantly improved for patients in the MO group treated with SLT compared to patients treated with RR/RFA (P = 0.017). Recurrence pattern was an independent prognostic factor for both OS [hazard ratio (HR) = 0.093, 95% confidence interval (CI): 0.026-0.337, P < 0.001] and DFS (HR = 0.318, 95% CI: 0.125-0.810, P = 0.016; HR = 3.334, 95% CI: 1.546-7.18, P = 0.002).

CONCLUSIONS

For patients with intrahepatic recurrent HCC, an MO recurrence pattern is associated with better long-term outcomes than the IM pattern. SLT is the preferred option for intrahepatic recurrent HCC, especially for MO cases.

Multicentric occurrence of hepatocellular carcinoma with nonalcoholic steatohepatitis

AIM

To reveal the manner of hepatocellular carcinoma (HCC) development in patients with nonalcoholic steatohepatitis (NASH) focusing on multicentric occurrence (MO) of HCC.

METHODS

We compared clinicopathological characteristics between patients with and without MO of HCC arising from NASH background. The clinical features were implicated with reference to the literature available.

RESULTS

MO of HCC was identified with histological proof in 4 out of 12 patients with NASH-related HCC (2 males and 2 females). One patient had synchronous MO; an advanced HCC, two well-differentiated HCCs and a dysplastic nodule, followed by the development of metachronous MO of HCC. The other three patients had multiple advanced HCCs accompanied by a well-differentiated HCC or a dysplastic nodule. Of these three patients, one had synchronous MO, one had metachronous MO and the other had both synchronous and metachronous MO. There were no obvious differences between the patients with or without MO in terms of liver function tests, tumor markers and anatomical extent of HCC. On the other hand, all four patients with MO of HCC were older than 70 years old and had the comorbidities of obesity, type 2 diabetes mellitus (T2DM), hypertension and cirrhosis. Although these conditions were not limited to MO of HCC, all the conditions were met in only one of eight patients without MO of HCC. Thus, concurrence of these conditions may be a predisposing situation to synchronous MO of HCC. In particular, old age, T2DM and cirrhosis were suggested to be prerequisite for MO because these factors were depicted in common among two other cases with MO of HCC under NASH in the literature.

CONCLUSION

The putative predisposing factors and necessary preconditions for synchronous MO of HCC in NASH were suggested in this study. Further investigations are required to clarify the accurate prevalence and predictors of MO to establish better strategies for treatment and prevention leading to the prognostic improvement in NASH.