The invention provides conjugates, comprising an organ, tissue or tumor cell homing molecule linked to a moiety. Such a moiety can be, for example, an oligonucleotide, small interfering RNA, gene, virus, protein, pharmaceutical or detectable agent. In addition the invention provides methods to diagnose or treat a pathology of the muscle or heart, by administrating to a subject having or suspected of having a pathology a molecule or conjugate that homes to, binds to and is taken up by the muscle cells or heart cells.