When comparing genes from published breast cancer signatures with the concurrent genes, 3 (AURKA, ERBB2, and GRB7) from the Oncotype DXTM signature, 5 from the Rotterdam signature (ACACB, ACOT11, CD44, TNFSF13, and UCKL1) and 20 (AK2, AURKA, BAG4, CSE1L, ERBB2, ETFA, FUBP1, GALE, GATM, GPSM2, GRB7, IDH2, ISG15, LRP8, NDUFB5, POLB, PTPRF, RCAN3, SLC9A3R , and STK24) from the Hu306 intrinsic signature were among the 629 concurrent genes in current study, highlighting the necessity of concurrent gene filtration in biomarker discovery and prognostic prediction. The gene discussed is CD44; the disease is breast cancer.