[6] NEIL1 recognizes (targets) and removes certain ROS-damaged bases and then incises the abasic site via β,δ elimination, leaving 3′ and 5′ phosphate ends.

NEIL1 is one of the DNA repair genes most frequently hypermethylated in head and neck squamous cell carcinoma (HNSCC).

When 8 DNA repair genes were evaluated in non-small cell lung cancer (NSCLC) tumors,[9] 42% were hypermethylated in the NEIL1 promoter region.

In colon cancer, germ line mutations in DNA repair genes cause only 2–5% of cases.

[15] NEIL1 deficiency causes brain damage and a functionally defective outcome in a mouse model of stroke.