GCNT2 and metastatic melanoma: Moreover, blood group I-antigens (branched poly-N-acetyllactosamines (poly-LacNAcs)) synthesized by I-branching β1,6 N-acetylglucosaminyltransferase 2 (GCNT2) are reported to be preferentially expressed on normal melanocytes, whereas metastatic melanoma cells display mainly i-antigens (linear poly-LacNAcs) with significant downregulation of the I-branching enzyme GCNT2 compared to normal melanocytes [8,9].