Therapeutic Effect of mRNA SARS-CoV-2 Vaccine on Melanoma Skin Metastases.

A unique case of multiple metastatic melanoma skin nodules regression in a heavily pretreated, 72-year-old Caucasian female, after administering the second dose of the SARS-CoV-2 mRNA Pfizer-BioNTech vaccine, is presented. Two days after vaccination, all her melanoma skin nodules became painful and were significantly reduced in size. Physical examination and ultrasound imaging confirmed the patient's observation. The effect was sustained, and further reduction of the nodules occurred after the third vaccine dose. One of the reduced nodules was removed, histologically examined, and its histopathology was compared to that of another such nodule removed and examined earlier. Distinct differences were observed between the two histopathologies, with the most notable the unexpected finding of the absence of infiltrating lymphocytes in the reducer nodule's melanoma tissue. Based on this observation, the possible immunological mechanism(s) leading to the vaccine's effect are speculated. More possible is the vaccine's antitumor and apoptotic activity via stimulation of the Tol Like Receptors 3, 7, and 8, and (downstream) the nuclear factor kappa-light-chain-enhancer of the activated B cells pathway of the non-lymphocytic immune effector cells.