Expression of α2‐macroglobulin receptor/low density lipoprotein receptor‐related protein is increased in reactive and neoplastic glial cells

α2‐Macroglobulin receptor/low density lipoprotein receptor‐related protein (α2M‐R/LRP) is a multi‐functional cell‐surface receptor that has been implicated in diverse physiologic processes. In normal human brain, α2M‐R/LRP is expressed principally by pyramidal neurons with localization to cell bodies and proximal processes. By contrast, α2M‐R/LRP is not present in either the cell bodies or processes of most normal macroglia (including astrocytes). In this investigation, we studied the expression of α2M‐R/LRP in the brain, following tissue injury or neoplastic transformation, by immunohistochemistry. Significantly increased α2M‐R/LRP immunoreactivity was identified in reactive astrocytes, indicating that expression of this receptor is regulated in vivo in response to brain injury. α2M‐R/LRP immunoreactivity was also detected in glial cell tumors; this finding is novel since malignant transformation is typically thought to turn off expression of this receptor.