Folate receptor beta (FRβ) has recently attracted considerable attention as a biomarker of tumor infiltrating macrophages, not only because its expression is restricted to myeloid cells (5), but also because FRβ is generally found to be upregulated on immunosuppressive myeloid derived suppressor cells (MDSCs) and tumor associated macrophages (TAMs) (6–8). Here, FOLR2 is linked to neoplasm.