Next generation sequencing of progressive colorectal liver metastases after portal vein embolization

Evaluation of two-stage hepatectomy using portal vein embolization for colorectal liver metastasis: a retrospective nationwide cohort survey in Japan

INTRODUCTION

Two-stage hepatectomy (TSH) enables patients to undergo surgery for colorectal liver metastasis (CRLM) which one-stage hepatectomy cannot remove. Although the outcome of TSH has been reported, there is no original report from Japan. The aim of this retrospective study was to evaluate the outcome of TSH in Japanese patients with CRLM.

METHODS

We conducted a retrospective cohort study using the nationwide database that included clinical information of 12,519 patients treated with CRLM between 2005 and 2017 in Japan. The primary outcome measure was overall survival. The second outcome measure was progression-free survival. Fisher's exact test, chi-squared test and Mann-Whitney U test were conducted to examine an intergroup difference. Univariate and multivariate analyses were performed using Cox regression model. Survival analysis was performed by Kaplan-Meier method and log-rank test.

RESULTS

Of the database, 53 patients undergoing TSH using portal vein embolization (PVE) were identified and analyzed. Their morbidity and in-hospital mortality rate at the second hepatectomy were 26.4% and 0.0%. The mean observation period was 21.8 months. The estimated 1-, 3- and 5-year overall survival rate were 92.5%, 70.8% and 34.7%. Multivariate analyses showed that more than 10 liver nodules significantly increased the mortality risk by 4.2-fold (95%CI 1.224-14.99, P= 0.023). Survival analysis revealed that repeat hepatectomy for disease progression after TSH was superior to chemotherapy in overall survival (mean: 49.6 vs. 18.7, months, P= 0.004).

CONCLUSION

In the Japanese cohort, TSH was confirmed to be a safety procedure with acceptable survival outcome. More than 10 liver nodules may be a predictor for unfavorable outcome of patients with CRLM undergoing TSH. Furthermore, repeat hepatectomy can be a salvage treatment for resectable intrahepatic recurrence after TSH.

Integration of Next-Generation Sequencing in the Surgical Management of Colorectal Liver Metastasis

Hepatic resection remains the treatment of choice for colorectal liver metastases. The advancement of surgical technique and use of perioperative systemic therapy has expanded the number and complexity of patients eligible for surgical resection. In recent years, investigation into gene mutations, such as RAS/RAF pathway, have led to targeted therapies that have significantly improved outcomes. Next-generation sequencing allows analysis of large number of genes that may have potential prognostic relevance in the clinical setting. This review summarizes the current applications of next-generation sequencing technology in metastatic colorectal cancer, focusing on its prognostic implications on patient management.

Metastatic colorectal cancer and type 2 diabetes: prognostic and genetic interactions

The present study was undertaken to analyze prognostic and genetic interactions between type 2 diabetes and metastatic colorectal cancer. Patients’ survival was depicted through the Kaplan–Meier product limit method. Prognostic factors were examined through the Cox proportional‐hazards regression model, and associations between diabetes and clinical‐pathologic variables were evaluated by the χ² test. In total, 203 metastatic colorectal cancer patients were enrolled. Lymph nodes (P = 0.0004) and distant organs (> 2 distant sites, P = 0.0451) were more frequently involved in diabetic patients compared with those without diabetes. Diabetes had an independent statistically significant negative prognostic value for survival. Highly selected patients with cancer and/or diabetes as their only illness(es) were divided into three groups: (a) seven oligo‐metastatic patients without diabetes, (b) 10 poly‐metastatic patients without diabetes, and (c) 12 poly‐metastatic diabetic patients. These groups of patients were genetically characterized through the Illumina NovaSeq 6000 (San Diego, CA, USA) platform and TruSigt™Oncology 500 kit, focusing on genes involved in diabetes and colorectal cancer. Gene variants associated with diabetes and cancer were more frequent in patients in group 3. We found that type 2 diabetes is a negative prognostic factor for survival in colorectal cancer. Diabetes‐associated gene variants could concur with malignancy, providing a rational basis for innovative models of tumor progression and therapy.

Regulation of Small GTPase Rab20 by Ikaros in B-Cell Acute Lymphoblastic Leukemia

Ikaros is a DNA-binding protein that regulates gene expression and functions as a tumor suppressor in B-cell acute lymphoblastic leukemia (B-ALL). The full cohort of Ikaros target genes have yet to be identified. Here, we demonstrate that Ikaros directly regulates expression of the small GTPase, Rab20. Using ChIP-seq and qChIP we assessed Ikaros binding and the epigenetic signature at the RAB20 promoter. Expression of Ikaros, CK2, and RAB20 was determined by qRT-PCR. Overexpression of Ikaros was achieved by retroviral transduction, whereas shRNA was used to knockdown Ikaros and CK2. Regulation of transcription from the RAB20 promoter was analyzed by luciferase reporter assay. The results showed that Ikaros binds the RAB20 promoter in B-ALL. Gain-of-function and loss-of-function experiments demonstrated that Ikaros represses RAB20 transcription via chromatin remodeling. Phosphorylation by CK2 kinase reduces Ikaros’ affinity toward the RAB20 promoter and abolishes its ability to repress RAB20 transcription. Dephosphorylation by PP1 phosphatase enhances both Ikaros’ DNA-binding affinity toward the RAB20 promoter and RAB20 repression. In conclusion, the results demonstrated opposing effects of CK2 and PP1 on expression of Rab20 via control of Ikaros’ activity as a transcriptional regulator. A novel regulatory signaling network in B-cell leukemia that involves CK2, PP1, Ikaros, and Rab20 is identified.