FKBP1A and histiocytic sarcoma: Similarly, MTOR (Mechanistic Target Of Rapamycin Kinase) gene that acts as the target for the cell-cycle arrest and immunosuppressive effects of the FKBP12 (12-kDa FK506-binding protein)-rapamycin complex was found to be significantly hypermethylated in peripheral blood samples of HS patients [11].