Although the proinflammatory cytokine interferon-gamma (IFN-gamma) has been generally thought to enhance antitumor immune responses and be involved in antitumor mechanisms of many other immunotherapy molecules, it has also been reported that IFN-gamma could promote tumor immune evasion. In this report, by using an ideal mouse model that expresses IFN-gamma locally in muscle, we demonstrate that sustained low-level expression of IFN-gamma promotes the development of several types of tumor including H22 hepatoma, MA782/5S mammary adenocarcinoma and B16 melanoma. However, transitory expression of IFN-gamma does not have such an effect. On the other hand, sustained high-level expression of IFN-gamma mediates significant antitumor effect on H22 hepatoma. Low level of IFN-gamma upregulates expression of PD-L1, PD-L2, CTLA-4 and Foxp3, which may partly account for the tumor immune evasion promoted by IFN-gamma. Furthermore, blockade of PD-L inhibits IFN-gamma's tumor-promoting effect. Our findings provide a mechanistic link between chronic inflammation and cancer and would have potential implications for cancer prevention and also for the design of cytokine-based cancer immunotherapy.

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Coronavirus disease 2019 (COVID-19) is a newly emerging infectious disease caused by the novel coronavirus SARS-CoV-2. It first became prevalent in Wuhan, Hubei, China in December 2019. COVID-19 was initially characterized by pneumonia of unknown etiology, accompanied by fever, dry cough and fatigue. Due to its highly infectious nature it rapidly led to widespread human infection, causing 80,924 confirmed cases and 3,140 mortalities in mainland China as of March 9, 2020. The present review highlights the prevalence of COVID-19 in China, the etiology, pathology, clinical presentation, laboratory and chest imaging tests, and treatment of this disease. Contents 1. Introduction 2. Epidemiology 3. Etiology 4. Pathogenesis 5. Pathology 6. Clinical characteristics 7. Laboratory and chest imaging tests 8. Treatment 9. Conclusion