FOLR2 and cancer: More recently, FR-β has been shown to be expressed on both malignant cells and tumor-associated macrophages from a wide variety of cancers, including cancers of the lung, breast, liver, brain, uterus, thyroid, stomach, ovary, head & neck, skin, kidney, pancreas, bladder, cervix, esophagus, prostate, testis, and colon [6, 22].