**5. COVID-19 and cancer**

COVID-19 by itself remains biologically novel and not much is known about the role of novel coronavirus SARS-CoV2 in cancer. Some critical questions that need to be answered are (1) Whether SARS-CoV-2 infection cause cancer? (2) Whether SARS-CoV-2 infection increases the risk of cancer? and, (3) Whether SARS-CoV-2 infection affects the survival of cancer patients?

Similar to other severe acute respiratory outbreaks (SARS-CoV, MERS-CoV), comorbidities such as hypertension and malignancy predispose COVID-19 positive patients to adverse clinical outcomes [1–4]. Whether SARS-CoV2 causes or modulates cancer pathobiology, is unknown. However, it is evident that patients undergoing cancer-associated treatments for example, chemo or radiotherapy and CAR-T cell therapy patients are at higher risk of becoming worse following COVID-19 infection [5, 6]. A recent study including 1,590 COVID-19 positive patients in China shows cancer as one of the more serious comorbidities that increase risk with respect to COVID-19 [4, 7]. Therefore, cancer patients receiving anti-tumor therapies should have vigorous screening for COVID-19 infection and their immunosuppressive treatment regimens and dosages potentially decreased in the case of COVID-19 coinfection [8]. For some patients, chemotherapy must be postponed until completion of the antiviral course of therapy, while others cannot be subjected to the viral infection therapy while under treatment for their cancer [9]. The symptoms of COVID-19 in cancer patients are mostly similar to the ones in general population (fever, coughing and shortness of breath) [10, 11]. However, cancer-associated treatments for example, steroids may suppress the fever symptom of COVID-19. The decision on treatment of a COVID-19 positive cancer patient depends on the type of cancer, stage of treatment, and severity of COVID-19. Immune dysregulation and chronic inflammation may be potential drivers of severe outcomes in COVID-19-positive cancer patients. Therefore, a better understanding of the mechanistic link between the two will help to prevent negative effects of infection and also enable the design of novel therapies that target cancer and COVID-19, and co-target both diseases.
