A possible mechanism for NK cell protection from metastasis was proposed by the authors, suggesting that in the case of heterozygous HLA-C expression (C1/C2), loss of one HLA-C allele (C1 or C2) by the tumor will potentially lead to loss of cell surface expression of a ligand that will no longer be recognized by its respective NK cell iKIR. Here, HLA-C is linked to neoplasm.