FRβ is present in the placenta, hematopoietic tissues such as the spleen, thymus, and bone marrow-derived myeloid cells.8 FRβ-expressing myeloid immune cells are present and vary dynamically during tumorigenesis, with the highest expression seen in tumor-associated macrophages (TAMs).9 FRβ is also considered a biomarker for M2 regulatory macrophage polarization and a potential emerging immunotherapy target.10 FRγ is unique among the FRs in that it is a secreted protein: it lacks the C-terminal hydrophobic glycophosphatidylinositol (GPI) membrane anchor that is found in all other FRs. The gene discussed is FOLR2; the disease is neoplasm.