Myeloperoxidase

Myeloperoxidase is a peroxidase enzyme that in humans is encoded by the MPO gene on chromosome 17. MPO is most abundantly expressed in neutrophil granulocytes, and produces hypohalous acids to carry out their antimicrobial activity.

Karimi et al. applied imaging mass cytometry to characterize the immunological landscape of 139 high-grade glioma and 46 brain metastases tumours from patients. Single-cell technology analysis of more than 1.1 million cells across 389 high-dimensional histopathology images enabled the spatial resolution of immune lineages and activation states, revealing differences in immune landscapes between primary tumors and brain metastases from diverse solid cancers. These analyses revealed cellular neighbourhoods associated with survival in patients with glioblastoma, which they leveraged to identify a unique population of myeloperoxidase (MPO)-positive macrophages associated with long-term survival. The findings provide insight into the biology of primary and metastatic brain tumours, reinforcing the value of integrating spatial resolution to single-cell datasets to dissect the microenvironmental contexture of cancer ¹⁾