We observed that under HD conditions or HIF-PH inhibition, human monocytes rapidly upregulate FcγRIIb, acquiring an FcγRIIbbright phenotype, to display levels exceeding other abundantly expressed surface antigens such as MHC Class I. Furthermore, monocytes obtained from RCC patients or tumor associated niches, such as in the pleural cavity of mesothelioma patients or breast cancer patient ascites, also possess an FcγRIIbbright phenotype, contending that this phenotype is physiologically relevant. This evidence concerns the gene FCGR2B and mesothelioma.