Analysis of the cellular origin of hepatocellular carcinoma by p53 genotype

DNA methylation consistency implicates the primary tumor cell origin of recurrent hepatocellular carcinoma

AIMS

To investigate if DNA methylation pattern assay could be a new approach to identifying the primary tumor cell origin of the recurrent hepatocellular carcinoma (HCC).

MATERIALS & METHODS

Methylation of 24 genes and expression of 22 cancer stem cell (CSC) biomarkers were quantitatively measured in 10 paired primary and recurrent HCC specimens. The HBV viral-host junctions were determined in six pairs of them with HBV infection.

RESULTS

Similar DNA methylation patterns were observed among nine of ten pairs of primary and recurrent tumors. In five of six paired specimens with HBV infection, exactly same HBV DNA integrations were identified in each paired tumors. The expression of seven CSC biomarkers increased significantly in either primary or recurrent tumor tissues.

CONCLUSION

Recurrent HCCs mostly originate from their primary tumors. Assay of DNA methylation patterns could provide a new approach to determining the origin of recurrent HCC.

Hepatic resection for hepatocellular carcinoma based on tumor hemodynamics

Survival or disease-free survival is not considered an appropriate surrogate outcome for the locoregional curability (i.e. surgical margin) of hepatectomy for hepatocellular carcinoma because these are greatly influenced by non-metastatic factors like multicentric carcinogenesis (MC) or liver function. Hepatocellular carcinoma metastasizes by hematogenous seeding; therefore, the tumor blood flow (TBF) drainage area is a high-risk area for intrahepatic metastasis, and can be identified by computed tomography under hepatic arteriography and completely resected as part of the surgical margin. The TBF pattern is classified into marginal, portal vein or hypovascular types. Partial hepatectomies were mostly performed in patients with marginal or hypovascular type, whereas anatomical surgery was frequently performed in those with portal vein type. Pathologically, nodules inside the TBF drainage area were moderately or poorly differentiated carcinomas, suggesting intrahepatic metastasis. In contrast, those outside the drainage area were frequently solitary and contained well-differentiated carcinoma, which is consistent with MC. The pattern of tumor recurrences after TBF-based hepatectomy is divided into two distinct groups - "a few nodules" and "many nodules in multiple segments or extrahepatic" - indicating that intrahepatic recurrences develop from MC and from circulating tumor cells in peripheral blood, respectively. Anatomical resection has not shown a survival benefit over that of TBF-based partial hepatectomy. TBF-based hepatectomy enables us to preserve liver function without compromising locoregional curability.

Methylation-based molecular margin analysis in hepatocellular carcinoma

The positive surgical margins are associated with postsurgical recurrence in hepatocellular carcinoma patients, and molecular margin analysis is considered more sensitive in detecting preneoplastic lesions than conventional histological margin examination. To evaluate the feasibility of methylation-based molecular margin analysis in HCC and explore its clinical application, we investigated CDKN2A methylation status in the surgical margins of 20 HCC patients using a nested BS-MSP protocol and compared the methylation patterns in resection margins with those in the corresponding tumor and adjacent nonmalignant tissues. The results showed that a considerable frequency (35%, 7 of 20) of CDKN2A methylation was present in histologically negative margins, and methylation pattern analysis might be valuable for studying the cellular origin of recurrent carcinoma. Therefore, methylation-based molecular surgical margin analysis offers a promising tool in prognosis for HCC patients who underwent hepatectomy.

A decade's studies on metastasis of hepatocellular carcinoma

Metastasis remains one of the major challenges before hepatocellular carcinoma (HCC) is finally conquered. This paper summarized a decade's studies on HCC metastasis at the Liver Cancer Institute of Fudan University. We have established a stepwise metastatic human HCC model system, which included a metastatic HCC model in nude mice (LCI-D20), a HCC cell line with high metastatic potential (MHCC97), a relatively low metastatic potential cell clone (MHCC97L) and several stepwise high metastatic potential cell clones (MHCC97H, HCCLM3, and HCCLM6) from their parent MHCC97 cell. Endeavors have been made for searching human HCC metastasis-related chromosomes/proteins/genes. Monogene-based studies revealed that HCC invasion/metastasis was similar to that of other solid tumors, and the biological characteristics of small HCC were only slightly better than that of large HCC. Using comparative genomic hybridization (CGH), fluorescence in situ hybridization (FISH), genotyping, cDNA microarray, and 2-dimensional gel electrophoresis, we obtained some interesting results. In particular, in collaboration with the National Institute of Health (NIH) in the United States, we generated a molecular signature that can classify metastatic HCC patients, identified osteopontin as a lead gene in the signature, and found that genes favoring metastasis progression were initiated in the primary tumors. We also found that chromosome 8p deletion, particularly in the region of 8p23, was associated with HCC metastasis. Cytokeratin 19 was identified as one of the proteins, which was found in MHCC97H, but not in MHCC97L cells. Experimental interventions using the high metastatic nude mice model have provided clues for the prevention of HCC metastasis. Translation from workbench to bedside demonstrated that serum VEGF, microvessel density, and p53 scoring may be of value for the prediction of postoperative metastatic recurrence. Interferon alpha proved effective for the prevention of recurrence both experimentally and clinically. In conclusion, HCC metastasis that probably initiated in the primary tumor is a multigene-involved, multistep, and changing process. The further elucidation of the mechanism underlying HCC metastasis will provide a more solid basis for the prediction and prevention of the metastatic recurrence of HCC.

Preventive treatments for recurrence after curative resection of hepatocellular carcinoma - A literature review of randomized control trials

To review the inhibitory effect of preventive approaches on recurrence after operation in patients with hepatocellular carcinoma (HCC), we summarized all available publications reporting randomized control trial indexed in PubMed. The treatment approaches presented above included pre-operative transcatheter arterial chemoembolization (TACE), post-operative TACE, systemic or locoregional chemotherapy, immunotherapy, Interferons and acyclic retinoic acid. Although no standard treatment has been established, several approaches presented promising results, which were both effective and tolerable in post-operative patients. Pre-operative TACE was not effective on prolonging survivals, while post-operative TACE was shown with both disease-free survival and overall survival benefits in some papers, however, it was also questioned by others. Systemic chemotherapy was generally not effective on prolonging survival but also poorly tolerated for its significant toxicities. Adoptive immunotherapy using LAK cells was proved to be beneficial to patients’ survival in a recent paper. Interferon α and Interferon β can inhibit recurrence in HCC patients with HCV infection background, though the mechanism is not fully understood. Acyclic retinoic acid was shown to decrease multi-centric recurrence after operation, which was reported by only one group. In conclusion, several adjuvant approaches have been studied for their efficacy on recurrence in HCC patients in randomized control trials; however, multi-centric randomized control trial is still needed for further evaluation on their efficacy and systemic or local toxicities; in addition, new adjuvant treatment should be investigated to provide more effective and tolerable methods for the patients with HCC after operation.

The role of des-gamma-carboxy prothrombin levels in hepatocellular carcinoma and liver tissues

We aimed to clarify the clinical significance of des-gamma-carboxy prothrombin (DCP) levels in both hepatocellular carcinoma (HCC) and liver tissues with a special reference to the relationship between DCP level in non-cancerous parts of the liver and the multicentric occurrence of HCC. Twenty-eight patients with HCC, who underwent hepatectomy, were studied. Surgical specimens were obtained from both HCC and non-cancerous liver of each patient. After the preparation of the liver tissues, including tissues with HCC, the DCP levels both in HCC and non-cancerous liver tissue were measured using an electro-chemiluminescence immunoassay. The correlation was investigated between DCP levels and other clinicopathological factors. The DCP level of HCC ranged from 55 to 77735 U/0.1 g tissue weight, with a median of 2801, while the DCP level of non-cancerous parts of the liver ranged from 24 to 721 U/0.1 g tissue weight, with a median of 86. The DCP level in the liver tissue in patients having a multicentric occurrence of HCC was significantly higher than that in patients without multicentric occurrence of HCC. The logarithm of the plasma DCP level correlated with that of the DCP level in HCC (correlation coefficient =0.46; P<0.05). No significant correlation was found between the DCP level in HCC and other clinicopathological parameters. The DCP level in non-cancerous parts of the liver with simultaneous multicentric occurrence of HCC was significantly higher than that in the liver without multicentric HCC. Furthermore, the DCP level in non-cancerous parts of the liver was one of the most important predictable factors of the multicentric occurrence of HCCs among various clinicopathological factors. Therefore, the DCP level may have an important role in hepatocarcinogenesis.