Figure 1.

Impacts of COVID-19 and cancer on each other. The SARS-CoV-2 infection may enhance the risk of cancer development and recurrence through induction of exhaustion of cytotoxic lymphocytes, stimulation of hyper-inflammatory responses, induction of oxidative stress, reduction of the number of lymphocytes and NK cells, down-regulation of IFN response, induction of the pro-tumoral cells such as MDSCs and M2 macrophages, downregulation of tumor suppressor proteins, and perhaps through re-activation of the oncogenic viruses. On the other side, the malignancy can enhance the susceptibility to SARS-CoV-2 infection and increases the severity of COVID-19-related complications through impairing both innate- and adaptive immune responses to virus as well as upregulation of angiotensin-converting enzyme 2 (ACE2) in certain cancers such as lung cancer.