Increased Response to Immune Checkpoint Inhibitors with Dietary Methionine Restriction in a Colorectal Cancer Model.

Dietary methionine restriction (MR), defined as a reduction of methionine intake by around 80%, has been shown to reproducibly decrease tumor growth and synergize with cancer therapies. In this study, we combined DMR with immune checkpoint inhibitors (ICIs) in a model of colon adenocarcinoma. In vitro, we observed that MR increased the expression of MHC-I and PD-L1 in both mouse and human colorectal cancer cells. We also saw an increase in the gene expression of STING, a known inducer of type I interferon signaling. Inhibition of the cGAS-STING pathway, pharmacologically or with siRNA, blunted the increase in MHC-I and PD-L1 surface and gene expression following MR. This indicated that the cGAS-STING pathway, and interferon in general, played a role in the immune response to MR. We then combined dietary MR with ICIs targeting CTLA-4 and PD-1 in an MC38 colorectal cancer tumor model developed in immunocompetent C57BL/6 mice. The combination treatment was five times more effective at reducing the tumor size than ICIs alone in male mice. We noted sex differences in the response to dietary MR, with males showing a greater response than females. Finally, we observed an increase in membrane staining for the PD-L1 protein in MC38 tumors from animals who were fed an MR diet. MHC-I was highly expressed in all tumors and showed no expression difference when comparing tumors from control and MR-treated mice. These results indicated that MR increased PD-L1 expression both in vitro and in vivo and improved the response to ICIs in mice.

Characterization of Morreton virus as an oncolytic virotherapy platform for liver cancers.

BACKGROUND: Morreton virus (MORV) is an oncolytic Vesiculovirus , genetically distinct from vesicular stomatitis virus (VSV). AIM: To report that MORV induced potent cytopathic effects (CPEs) in cholangiocarcinoma (CCA) and hepatocellular carcinoma (HCC) in vitro models. APPROACH AND RESULTS: In preliminary safety analyses, high intranasal doses (up to 10 10 50% tissue culture infectious dose [TCID 50 ]) of MORV were not associated with significant adverse effects in immune competent, non-tumor-bearing mice. MORV was shown to be efficacious in a Hep3B hepatocellular cancer xenograft model but not in a CCA xenograft HuCCT1 model. In an immune competent, syngeneic murine CCA model, single intratumoral treatments with MORV (1 × 10 7 TCID 50 ) triggered a robust antitumor immune response leading to substantial tumor regression and disease control at a dose 10-fold lower than VSV (1 × 10 8 TCID 50 ). MORV led to increased CD8 + cytotoxic T cells without compensatory increases in tumor-associated macrophages and granulocytic or monocytic myeloid-derived suppressor cells. CONCLUSIONS: Our findings indicate that wild-type MORV is safe and can induce potent tumor regression via immune-mediated and immune-independent mechanisms in HCC and CCA animal models without dose limiting adverse events. These data warrant further development and clinical translation of MORV as an oncolytic virotherapy platform.

Repurposing live attenuated trivalent MMR vaccine as cost-effective cancer immunotherapy.

It has long been known that oncolytic viruses wield their therapeutic capability by priming an inflammatory state within the tumor and activating the tumor immune microenvironment, resulting in a multifaceted antitumor immune response. Vaccine-derived viruses, such as measles and mumps, have demonstrated promising potential for treating human cancer in animal models and clinical trials. However, the extensive cost of manufacturing current oncolytic viral products makes them far out of reach for most patients. Here by analyzing the impact of intratumoral (IT) administrations of the trivalent live attenuated measles, mumps, and rubella viruses (MMR) vaccine, we unveil the cellular and molecular basis of MMR-induced anti-cancer activity. Strikingly, we found that IT delivery of low doses of MMR correlates with tumor control and improved survival in murine hepatocellular cancer and colorectal cancer models via increased tumor infiltration of CD8+ granzyme B+ T-cells and decreased macrophages. Moreover, our data indicate that MMR activates key cellular effectors of the host's innate and adaptive antitumor immunity, culminating in an immunologically coordinated cancer cell death. These findings warrant further work on the potential for MMR to be repurposed as safe and cost-effective cancer immunotherapy to impact cancer patients globally.

Morphology of tumor and nontumor tissue in liver resection specimens for hepatocellular carcinoma following nivolumab therapy.

Nivolumab is an immune checkpoint inhibitor (ICI) approved for treatment of many cancers, including hepatocellular carcinoma (HCC). Liver injury is a known complication in patients treated with nivolumab for nonliver tumors. To date, the morphologic changes to tumor and nontumor liver have not been well-characterized in HCC patients. We identified 20 patients who underwent partial hepatectomy or liver transplantation after receiving nivolumab for HCC. Demographics, laboratory values, and imaging results were obtained from medical records. All available slides from resection specimens were evaluated for tumor necrosis, tumor-infiltrating lymphocytes (TILs), and features of liver injury. Patients in the study included 16 males and 4 females with median age of 56 years. The underlying liver disease was HBV in 10, HCV in 6, and unknown/other in 4. Twelve patients were treated with nivolumab in the neoadjuvant setting, whereas eight were treated with nivolumab, usually along with other therapies, before undergoing liver transplantation. On review of resection specimens, three patients (all from the neoadjuvant group) demonstrated marked treatment response attributable to nivolumab. TILs were present in 17/20 cases. One case that showed treatment response in the neoadjuvant group demonstrated non-necrotizing granulomas and prominent bile duct intraepithelial lymphocytes (IELs) in the nontumor liver. One case from the transplant group showed bile duct damage and prominent ductular reaction after long-term nivolumab therapy (32 doses). Our findings indicate that nivolumab is effective in a subset of patients, including in the neoadjuvant setting. Granulomas and bile duct IELs are rare findings in cases treated with nivolumab but, when seen, may indicate potential response to therapy. Bile duct damage and ductular reaction may be manifestations of long-term nivolumab therapy. Future prospective and longitudinal studies with pretreatment tumor biopsies may help identify patients apt to respond to ICI therapy and further characterize patterns of ICI-related liver injury.

Direct-Acting Antiviral Treatment of Patients with Hepatitis C Resolves Serologic and Histopathologic Features of Autoimmune Hepatitis.

Patients with hepatitis C virus (HCV) often have elevated serum markers and histologic features of autoimmune hepatitis (AIH). We evaluated an HCV-positive (HCV+) study group that had elevated serum markers of AIH before starting direct-acting antiviral (DAA) therapy (n = 21) and compared them to an HCV+ control group that did not have laboratory studies suggesting AIH (n = 21). Several patients in the study (17/21) and control (11/21) groups had liver biopsies before DAA treatment, and many were biopsied due to elevated serum markers of AIH. Evaluation of pre-DAA treatment liver biopsies showed histologic features suggestive of AIH in 64.7% (11/17) of the study group and 45.5% (5/11) of the control group. Patients who were HCV+ with elevated serum markers of AIH had significantly increased hepatitis activity (P < 0.001) and slightly increased fibrosis stages (P = 0.039) in their pretreatment liver biopsies compared to controls. We hypothesized that the elevated serum markers and histologic features of AIH would resolve following DAA treatment. Serum markers of AIH in the study group began decreasing by 6 months posttreatment, and 52.4% (11/21) had complete resolution. Alanine aminotransferase levels significantly decreased into the normal range for all patients (21/21). Even patients that had persistence of serum markers of AIH after DAA treatment had normal transaminases. Six patients from the study patient group and 4 patients from the control group had follow-up liver biopsies after DAA treatment, and all biopsies showed resolution of the histologic features of AIH. Conclusion: The majority of HCV+ patients that have serum markers and/or histopathologic features of AIH should initially be treated with DAA.

Rare Mesenchymal Breast Entities that Mimic Malignancy: A Single-institution Experience of a Challenging Diagnosis.

Background Benign mesenchymal tumors of the breast are rare and may mimic invasive carcinoma on imaging and morphology, thus becoming clinically challenging for clinicians, radiologists, and pathologists. To improve the understanding of these lesions and to avoid erroneous diagnosis and inappropriate treatment, we report our institution's experience with seven cases of granular cell tumor (GCT) and myofibroblastoma (MFB) in the past 10 years. Materials and methods Seven cases of benign mesenchymal tumors of the breast were identified at the University of Texas Medical Branch from 2008 to 2018. Breast biopsies were collected from all patients after mammography and ultrasound imaging classified their results as suspicious or highly suggestive of malignancy by the Breast Imaging Reporting and Data System (BI-RADS ≥ 4A). All cases were reviewed to study the morphologic features and their immunoprofiles. The demographic characteristics, methods of treatment, postoperative pathological results, and follow-up results of the cases were then analyzed and compared to peer-reviewed literature. Results The study consisted of five females and two males with a mean age of 50 years in the GCT patients and 62 years in MFB patients. We identified four cases of GCT and three cases of MFB. The mean tumor size was 1.9 cm. Clinically, five patients presented with a palpable nontender mass, one with breast asymmetry, and one was asymptomatic. All patients underwent imaging studies prior to core needle biopsy. BI-RADS was ≥4B in patients with GCT and 4A-C in MFB. Definitive diagnosis was made by histopathology and confirmed by immunohistochemistry in accordance with the features described in the literature. Six patients underwent wide excision. The mean follow-up duration was 44.5 months. All patients remained well, without recurrence. Conclusions MFB and GCT can mimic malignant neoplasms and the clinical significance of these entities lies primarily in their recognition as distinctive benign neoplasms. The gold standard for the diagnosis of GCT and MFB is histopathology. All the cases in our series were clinically or radiologically mistaken for carcinoma, which has been largely reported in the literature. Pathologists should bear this in mind to avoid misdiagnosis and unnecessary treatment.

Budd-Chiari syndrome: a rare and life-threatening complication of Crohn's disease.

Budd-Chiari syndrome (BCS) is characterised by obstruction of hepatic venous outflow and may be triggered by the prothrombotic state associated with inflammatory bowel disease (IBD). We reported a case of Crohn's disease (CD) that presented with anasarca, ascites, symptomatic hepatomegaly, elevated liver enzymes, increased prothrombin time and low albumin. Oesophagogastroduodenoscopy and colonoscopy confirmed active CD. Abdominal CT showed hepatic vein thrombosis. Liver biopsy revealed severe perivenular sinusoidal dilation with areas of hepatocyte dropout, bands of hepatocyte atrophy and centrizonal fibrosis, suggestive of BCS. The patient was treated with steroids for CD and systemic anticoagulants for BCS. His liver function and enzymes normalised, and he reported symptomatic improvement. The precise mechanism responsible for increased hypercoagulability in IBD remains unclear. Early recognition and treatment for possible thrombotic complications of CD is critical to prevent potentially fatal events like pulmonary embolism or liver failure.

Clinical and histopathological features and immunoreactivity of human choroidal and ciliary melanomas as prognostic factors for metastasis and death.

PURPOSES: To determine the relationship between immunohistochemical reactivity to osteopontin, vimentin, keratin 8/18, LZTS1, and beta-catenin and clinical and histopathological prognostic factors for metastasis and death in archival specimens of primary uveal melanomas, and the prognostic value of the evaluated study variables for death from metastasis. METHODS: Retrospective analysis of clinical records and formalin-fixed, paraffin-embedded slides of primary uveal melanomas treated by enucleation during May 1 1999, through June 30 2009. Immunofluorescent staining of each tumor was assessed on newly prepared histologic slides after the application of antibodies directed against five biomarkers associated with unfavorable prognosis in uveal melanoma. RESULTS: After exclusions, our study group consisted of 82 cases. Immunofluorescence was observed in 40.2% of specimens evaluated for keratin, 50.0% evaluated for osteopontin, 26.8% evaluated for ß-catenin, 65.9% evaluated for vimentin, and 70.7% evaluated for LZTS1. Through available follow-up, 27 patients (32.9%) were dead of confirmed or suspected metastatic uveal melanoma. None of the patients whose tumor exhibited strong immunoreactivity to ß-catenin died of metastasis. In contrast, patients whose tumor exhibited immunoreactivity of any intensity to LZTS1 were more likely to develop metastasis. In multivariate Cox proportional hazards modeling, a composite variable that took into account the immunostaining for both ß-catenin and LZTS1 had a statistically significant relationship with patient's survival time. CONCLUSIONS: Our study suggests that conventional clinical and histopathological prognostic factors, and immunoexpression of ß-catenin and LZTS1 combined may allow better prognostication of metastasis than clinical and histomorphological factors alone.