The folate receptor (FR) is a cell over expressed on the surface of certain cancers, this occurs most frequently in ovarian cancers. Some normal tissues also express the FR, however in these normal tissues, the FR is usually located on the tissue surface that is inaccessible to circulating drugs. As such, drugs which target the FR may potentially be used to target cancers which overexpress the FR while reducing toxicity to normal tissues. Therefore the ability to measure FR levels from different cancer types may help to select patients who are most likely to benefit from treatment with FR targeted therapies. Once such drug BGC945 is currently being tested in preclinical study at the Institute of Cancer Research