LNPEP and Alzheimer disease: A study examined the expression of key RAS genes and the Leucyl and Cystinyl Aminopeptidase (LNPEP) gene in postmortem frontal cortex brain tissue from individuals with various forms of dementia—specifically, (a) AD, (b) vascular dementia, and (c) AD coupled with vascular dementia—alongside samples from individuals experiencing normal aging.