HMGCS2 and FABP7 in combination with the panel published in our previous studies, 15-PGDH+, HMGCR+ and ACSM1+ may represent the golden standard for defining the breast apocrine phenotype. Expression of FABP7 and HMGCS2 by invasive apocrine cancer was further demonstrated by IHC using a well characterized set of apocrine GNE-7915 carcinomas in which more than 90% of the tumor cells exhibited cytological features typical of apocrine cells. FABP7 positives were found in 78% of all IAC cases and in 96% of ADCIS and only in 14 out of the 210 non-IAC breast tumor subtypes. Tang and coauthors reported that FABP7 overexpression exhibited a strong relationship with triple-negative cases and the basal-like subtype. Our results confirmed partially a higher frequency of FABP7 positives in TNBC group as compared to the other subtypes of breast tumors. These findings are also in the line with the studies showing that FABP7 is associated with the basal phenotype and patient outcome in human breast cancer. Fluocinonide Importantly, our data have demonstrated various sub-cellular localization of FABP7 in apocrine carcinomas and have shown that, unlike ADCIS, in which FABP7 was detected mainly in the cytoplasm, in IACs FABP7 was also observed in nuclei, which is in the line with recent data demonstrating that nuclear location is associated with a more aggressive phenotype of breast cancer. It was also shown, that FABP7 overexpression is correlated with pure glioblastoma histology and that nuclear expression of FABP7 is more specifically associated with more invasive tumors. Taken together these data support the contention that translocation of FABP7 between nuclei and cytoplasm may play a role in tumor progression and further investigation should be undertaken to understand roles of FABP7 signaling and intracellular traffic in tumor biology. To our knowledge, there are no data available on the expression and activity on the protein level of HMGCS2, the gene that controls the anabolic ketogenic pathway in breast cancer. Here we have shown for the first time that HMGCS2 was up-regulated in ADCIS and IAC and only rarely found in non-apocrine breast carcinoma.