gp100:209-217(210m) gp100:209-217(210m) gp100:209-217(210m) is a synthetic peptide cancer vaccine consisting of amino acid residues 209 through 217 of the glycoprotein 100 (gp100) melanoma antigen, with a methionine substitution at position 210. it is often referred to as the gp100 cancer vaccine which can also include other peptides based on gp100 (for example gp100:280-288(288v)). clinical trials it gave good results in a trial for advanced melanoma when used in combination with interleukin-2.another trial against ipilimumab in advanced melanoma suggested ipilimumab may be better than the gp100 vaccine alone.