Park et al. performed an analysis on young ER+ Korean breast cancer patients; these patients were subdivided into three subgroups: A, chromosomal-stable, mainly enriched in luminal A (91%); B, a mixture of luminal A and B (89%); and, C, including HER2-enriched and luminal B types (64%) [329]. This evidence concerns the gene ERBB2 and breast carcinoma.