NRP1 and posterior cortical atrophy: In the classic case-control PCa EWAS analysis, the top associations included variants in HCP5 and RFX6, and near IATPR and NRP1. The histocompatibility leucocyte antigen (HLA) complex P5 (HCP5) is a long non-coding RNA located in the HLA class I region and has shown aberrant expression in multiple cancers, including PCa27.