MC1R and melanoma: Melanoma is an aggressive disease and metastatic stage-IV melanoma is difficult to treat despite recent advances in immunotherapies.23–26 Median survival ranges from 8 to 12 months with standard-of-care treatment, including immunotherapeutic drugs such as ipilimumab and nivolumab.23–26 Novel nanomolecular drug agents constructed from silica permit MC1R targeting and now enable selective delivery of the α-particle emitters actinium-225, yielding a potent new treatment option for metastatic melanoma.