Faculty Bibliography

INTRODUCTION/BACKGROUND:Laparoscopic approach to liver resection is feasible and safe, though its utilization with intrahepatic cholangiocarcinoma (ICC) remains poorly documented. We sought to evaluate the use laparoscopy for ICC, and to examine adherence to oncologic standards. METHODS:The National Cancer Database was queried for patients who underwent resection for ICC. Patients were stratified by laparoscopic (LLR) versus open liver resection (OLR). Clinicopathologic parameters and hospital volumes were recorded. RESULTS:In total, 2309 patients with ICC underwent hepatic resection (1997 OLR, 312 LLR) between 2010 and 2015. LLR increased from 12 to 16% during the study period and was utilized more commonly than OLR for wedge and segmental resections (56% vs. 33%, p < 0.001). Nodal evaluation was performed in 58% of all patients with ICC and was significantly more common in patients undergoing OLR (61%, n = 1210) versus LLR (39%, n = 120), p < 0.001. Of the 120 patients undergoing LLR with any nodal evaluation, 31% (n = 37) had a single node evaluated. Patients who underwent LLR were less likely to have ≥ 6 lymph nodes evaluated compared with those who underwent OLR (9% vs. 15%, respectively, p < 0.001). CONCLUSIONS:The use of laparoscopy for ICC is associated with an exacerbation of inadequate nodal evaluation compared with open resections.

BACKGROUND:Portal lymphadenectomy for intrahepatic cholangiocarcinoma (ICC) is encouraged for staging purposes, though it is under-utilized for clinically early-stage tumors. We sought to determine if any factor knowable prior to resection influences rates of portal lymph node metastases. METHODS:The Surveillance, Epidemiology, and End Results (SEER) Program (1973-2014) database was queried to identify patients with T1/T2 ICC undergoing resection. Patients were stratified by lymph node (LN) status. Patients deemed LN negative required examination of six or more LNs (AJCC guidelines). RESULTS:One-hundred and fifty-two patients were included in the analysis (LN negative: 38, LN positive: 114). Patients with LN negative cancers experienced prolonged overall survival as compared to patients with positive LNs (median 77 months vs 19 months, respectively p < 0.001). Twelve patients had well-differentiated tumors (G1), 92 patients had moderately-differentiated tumors (G2) and 58 patients had poorly-differentiated tumors (G3). Tumor grade (OR 3.9, CI 1.1-13.7, p = 0.031) and male sex (OR 2.6, CI 1.1-6.1, p = 0.022) were associated with positive LNs on multivariable logistic regression analysis. CONCLUSION:Intermediate/High grade and male sex are associated with high rates of lymph node metastasis for patients with early-stage ICC, which portends abbreviated overall survival.

BACKGROUND & AIMS:Cytokine-induced killer (CIK) cell-based immunotherapy is effective as an adjuvant therapy in early stage hepatocellular carcinoma (HCC) but lacks efficacy in advanced HCC. We aimed to investigate immune suppressor mechanisms in HCC, focusing on the role of myeloid-derived suppressor cells (MDSCs) in response to CIK therapy. METHODS:MDSCs were quantified by flow cytometry and quantitative real-time PCR. Cytokines were detected by cytokine array. A lactate dehydrogenase cytotoxicity assay was performed in the presence or absence of MDSCs to study CIK function against HCC cells in vitro. An FDA-approved PDE5 inhibitor, tadalafil, was used to target MDSCs in vitro and in vivo. Two different murine HCC cell lines were tested in subcutaneous and orthotopic tumor models in C57BL/6 and BALB/c mice. The antitumor effects of human CIKs and MDSCs were also tested in vitro. RESULTS:MDSCs. Treatment of MDSCs with a PDE5 inhibitor suppressed MDSC suppressor function and enhanced CIK activity against human HCC cell lines in vitro. CONCLUSION:Our results suggest that targeting MDSCs is an efficient strategy to enhance the antitumor efficacy of CIKs for the treatment of patients with HCC. LAY SUMMARY:Cytokine-induced killer cells are a mixture of immune cells given to eliminate cancer cells. However, not all patients respond to this treatment. Herein, we show in 2 different liver cancer models that myeloid-derived suppressor cells are increased in response to cytokine-induced killer cell therapy. Targeting these myeloid-derived suppressor cells may provide an additional therapeutic benefit alongside cytokine-induced killer cell therapy.

BACKGROUND:Metastatic squamous cell carcinoma (SCC) to the axillary or inguinal lymph nodes from an unknown primary source is rarely encountered. We sought to evaluate a cohort of patients with metastatic SCC managed by lymphadenectomy to determine their survival and to determine which clinicopathologic factors were associated with outcome. METHODS:All patients undergoing axillary or inguinal lymphadenectomy for SCC at our institution were identified retrospectively. Patients were stratified by unknown primary (UP) vs known skin primary (KP) tumors. Pertinent data on patient, tumor, and treatment variables was collected. RESULTS:We identified 51 patients who met inclusion criteria. Of those, 20 patients (39%) had UP metastatic SCC and 31 patients (61%) had KP. The 5-year overall survival for UP was 65%, as compared to 49% for KP (p = 0.16). Cumulative incidence of recurrence was 46%. Cox regression failed to demonstrate a significant association between KP vs UP, HPV status, chemotherapy, or radiation with survival. CONCLUSIONS:Nearly two-thirds of patients undergoing axillary or inguinal lymphadenectomy for metastatic SCC of unknown primary were alive five years following the procedure.

Mouse models are the basis of preclinical and translational research in hepatocellular carcinoma (HCC). Multiple methods exist to induce tumour formation in mice, including genetically engineered mouse models, chemotoxic agents, intrahepatic or intrasplenic injection of tumour cells and xenograft approaches. Additionally, as HCC generally develops in the context of diseased liver, methods exist to induce liver disease in mice to mimic viral hepatitis, fatty liver disease, fibrosis, alcohol-induced liver disease and cholestasis. Similar to HCC in humans, response to therapy in mouse models is monitored with imaging modalities such as CT or MRI, as well as additional techniques involving bioluminescence. As immunotherapy is increasingly applied to HCC, mouse models for these approaches are required for preclinical data. In studying cancer immunotherapy, it is important to consider aspects of antitumour immune responses and to produce a model that mimics the complexity of the immune system. This Review provides an overview of the different mouse models of HCC, presenting techniques to prepare an HCC mouse model and discussing different approaches to help researchers choose an appropriate model for a specific hypothesis. Specific aspects of immunotherapy research in HCC and the applied mouse models in this field are also highlighted.

A growing understanding of the immune system and its anti-tumor functions has been imperative for the comprehension of malignant processes and beneficial in the pursuit of effective cancer treatments. To defend the body, immune cells must be able to differentiate between self and foreign cells using checkpoints, allowing the immune cells to attack foreign cells. Among the different types of immune target therapies recently developed, checkpoint inhibitors have come to the forefront in cancer treatment, encouraging their study in numerous different types of cancer, including hepato-pancreato-biliary malignancies (HPB). Traditionally, these malignancies have been treated with standard cytotoxic chemotherapy, but with little benefit in the metastatic setting. However, impressive results with checkpoint inhibitor therapy have been noted in a number of cancers as these agents enable immune cells to kill cancer cells more efficiently. Two classes of checkpoint inhibitors being extensively studied are inhibitors of cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) ligand and programmed cell death protein 1 and its ligand (PD-1 and PD-L1). Checkpoint inhibitors have an advantage over other types of immunotherapies, such as cell-based therapies, in that they are commercially available and can be given to patients with a range of pathologies and regardless of HLA status. Herein, we will discuss the application of immune checkpoint inhibitors to HPB malignancies as well as the limitations of these medications in these cancers.

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related death worldwide. Immune checkpoint blockade with anti-CTLA-4 and anti-PD-1 antibodies has shown promising results in the treatment of patients with advanced HCC. The anti-PD-1 antibody, nivolumab, is now approved for patients who have had progressive disease on the current standard of care. However, a subset of patients with advanced HCC treated with immune checkpoint inhibitors failed to respond to therapy. Here, we provide evidence of adaptive resistance to immune checkpoint inhibitors through upregulation of indoleamine 2,3-dioxygenase (IDO) in HCC. Anti-CTLA-4 treatment promoted an induction of IDO1 in resistant HCC tumors but not in tumors sensitive to immune checkpoint blockade. Using both subcutaneous and hepatic orthotopic models, we found that the addition of an IDO inhibitor increases the efficacy of treatment in HCC resistant tumors with high IDO induction. Furthermore, in vivo neutralizing studies demonstrated that the IDO induction by immune checkpoint blockade was dependent on IFN-γ. Similar findings were observed with anti-PD-1 therapy. These results provide evidence that IDO may play a role in adaptive resistance to immune checkpoint inhibitors in patients with HCC. Therefore, inhibiting IDO in combination with immune checkpoint inhibitors may add therapeutic benefit in tumors which overexpress IDO and should be considered for clinical evaluation in HCC.

The prevalence of non-alcoholic fatty liver disease (NAFLD) and its advanced form, nonalcoholic steatohepatitis (NASH), is increasing, and as such its contribution to the development of hepatocellular carcinoma is also rising. NAFLD has been shown to influence the immune tumor microenvironment. Therefore, development of pre-clinical mouse models in the context of NAFLD are increasingly important. Here, we describe a mouse model designed to recapitulate the findings of NAFLD followed by rapid induction of orthotopic liver tumors with intrahepatic tumor injection. Additionally, we utilized bioluminescent imaging to monitor tumor growth and response to therapy. The development of one dominant tumor nodule allows precise separation of tumor and liver tissue. This is useful for immunotherapy studies as mononuclear cells from the tumor and the surrounding liver tissue can be analyzed separately.

Hepatocellular carcinoma (HCC) is a common cause of cancer-related death worldwide. As obesity and diabetes become more prevalent, the contribution of non-alcoholic fatty liver disease (NAFLD) to HCC is rising. Recently, we reported intrahepatic CD4⁺ T cells are critical for anti-tumor surveillance in NAFLD. Lipid accumulation in the liver is the hallmark of NAFLD, which may perturb T cell function. We sought to investigate how the lipid-rich liver environment influences CD4⁺ T cells by focusing on carnitine palmitoyltransferase (CPT) family members, which control the mitochondrial β-oxidation of fatty acids and act as key molecules in lipid catabolism. Linoleic acid (C18:2) co-localized within the mitochondria along with a corresponding increase in CPT gene upregulation. This CPT upregulation can be recapitulated by feeding mice with a high-C18:2 diet or the NAFLD promoting methionine-choline-deficient (MCD) diet. Using an agonist and antagonist, the induction of CPT genes was found to be mediated by peroxisome proliferator-activated receptor alpha (PPAR-α). CPT gene upregulation increased mitochondrial reactive oxygen species (ROS) and led to cell apoptosis. In vivo, using liver-specific inducible MYC transgenic mice fed MCD diet, blocking CPT with the pharmacological inhibitor perhexiline decreased apoptosis of intrahepatic CD4⁺ T cells and inhibited HCC tumor formation. These results provide useful information for potentially targeting the CPT family to rescue intrahepatic CD4⁺ T cells and to aid immunotherapy for NAFLD-promoted HCC.