MDSCs are capable of suppressing the immune system, primarily by acting on T cells, through an abundance of mechanisms, including arginine metabolism by arginase I and inducible nitric oxide synthase (iNOS), reactive oxygen spedes (ROS) production, prostaglandin E2 production via cydooxygenase 2 expression (Take 2020), TGF-β and interleukin-10 release, and indoleamine 2,3-dioxygenase synthesis (Groth 2019), and therefore if stress leads to an increase in MDSCs, this is suggestive of impaired anti-tumour immunity. Here, NOS2 is linked to neoplasm.