To enable analysis of the KIR-ligand-matching status, breast cancer cell lines were geno- and phenotyped for HLA class I. The genotype of MCF7 cells was determined as HLA C1−, C2+, and Bw4+ and the genotype of SKBR3 as HLA C1+, C2−, and Bw4−. Here, C2 is linked to breast cancer.