Breslow's research has focused on the genetic factors that govern an individual's predisposition to develop
atherosclerosis. and in the early 1980s, with Vassilis Zannis, he was one of the earliest to dissect the different
variants of human
apolipoprotein E (ApoE), a component of
very low-density lipoprotein. People with different ApoE variants are now known to have different risks not only of heart disease but also of
Alzheimer's disease.
Nobuyo Maeda's group at the
University of North Carolina at Chapel Hill also independently created ApoE
knockouts (
apoe−/−) that developed atherosclerosis at the same time. The ApoE knockout was the earliest mouse model of the disease, and has been widely used in atherosclerosis research. His group has subsequently researched other genes associated with atherosclerosis, and for example, in 2003, were among the first to identify and characterize
PCSK9, which encodes an enzyme acting in a novel cholesterol regulatory pathway.
Antibodies targeting PCSK9 were approved by the US
FDA as a novel class of cholesterol-lowering drugs in 2015. ==Awards and honours==