Along this line, newly developed CB2 PET ligands including, but not limited to, thiazole-[194, 195], pyridine-[196-198], thiophen-[199] and oxoquinoline-[200-204]-based probes, could be of use in future studies assessing microglial activation in response to immunotherapy in MS. The gene discussed is CNR2; the disease is myeloid sarcoma.