The APIS Breast Cancer Subtyping Kit is an mRNA-based assessment of the three biomarkers routinely assessed in all newly diagnosed breast cancers (BC), estrogen receptor (ER), progesterone receptor (PR), and HER2 as well as an additional four genes that create a novel proliferation signature, MKI67, PCNA, CCNA2, KIF23. Taken together the data is used to produce a molecular sub-type for every sample. The kit was evaluated against the current standard protocol of immunohistochemistry (IHC) and/or in situ hybridization (ISH) in breast cancer patients. The data was presented at the weekly breast Multidisciplinary Team (MDT) meeting. 98 consecutive cases of pre-operative breast cancer core biopsies and two core biopsy of nodal metastases yielding 100 cases were assessed. IHC and APIS Results were available for 100 and 99 cases. ER was concordant in 97% cases, PR in 89% and HER2 results were concordant with IHC/ISH in 100% of the cases. Ki-67 IHC was discordant in 3% cases when compared with MK167 alone but discordant in 24% when compared with the four gene proliferation signature. In conclusion, our study, indicates that the APIS Breast Cancer Subtyping Kit is highly concordant when compared to the results produced for ER/PR/HER2 by IHC and/or ISH. The assay could play a role in the routine assessment of newly diagnoses Breast Cancer (BC) specimens.