FIG. 4.

The principal source of a high and sustained level of NO^• is the NOS2. However, NO^• produced by NOS2 and NOS3 is implicated in pancreatic cancer progression. NO^• signaling is reported to have both pro- and antitumorigenic functions. Further mechanistic, functional, preclinical, and clinical studies are warranted to guide the potential therapeutic benefits of NO^•-based or NO^•-targeted treatment strategies. To see this illustration in color, the reader is referred to the web version of this article at www.liebertpub.com/ars