MYL is an abbreviation for myosin light chain. Myosin light chains are unique and have their own characteristics, unlike heavy chains. They are not considered to be "myosin" but rather a component of the macromolecular complex that constitutes a functional globulin. The myosin light chain can be composed of two smaller subunits weighing between 17 and 22 kDa of hexamer myosin II. Each pair of subunits is unique. The myosin light chain was discovered by Chinese biochemist Cao Tianqin when he was a graduate student at Cambridge University in the UK. Indium (111In) imciromab (trade name Myoscint) is a mouse monoclonal antibody labeled with the radioisotope indium-111. It was used for cardiac imaging but was withdrawn in 1993.