In a 2007 study, the differential expression levels of 38 miRNAs in breast cancer tumor samples enabled researchers to classify 51 out of 93 tumor samples, including 16 basal-like tumors, 15 luminal A, 9 luminal B, 5 HER2-positive, and 6 normal-like tumors [87]. This evidence concerns the gene ERBB2 and breast carcinoma.