Reduced expression of soluble guanylyl cyclase α1- and β1-subunits in arterial smooth muscle cells adjacent to oropharyngeal squamous cell carcinoma tumors is associated with impaired nitric oxide-mediated vasodilation and reduced suppression of smooth muscle proliferation, contributing to tumor-associated vascular growth.

Tumor tissue produces high levels of reactive oxygen molecules that damage a key enzyme in artery walls. This enzyme normally tells the artery to relax and stop growing when it detects a signal from nitric oxide. When the enzyme breaks down, the artery no longer responds to nitric oxide, so it keeps growing and forming new blood vessels that feed the tumor.