However, up to now only few approaches have entered clinical routine such as unspecific immune stimulation by Bacillus Calmette–Guérin (BCG) instillations to treat non-muscle invasive bladder cancer after surgical ablation (173) or the immunomodulating anti-CTLA4 mAb Ipilimumab for metastatic melanoma or prostate cancer (174), as well as aHSCT for the treatment of myeloid leukemias (175) and the prostate antigen-specific DC-based vaccine Sipuleucel-T (Provenge®) for hormone-refractory prostate cancer (176). Here, CTLA4 is linked to metastatic melanoma.