Expression of cell metabolism-related genes in different molecular subtypes of triple-negative breast cancer

Aims and background. We evaluated the difference in and significance of cancer cell metabolism by molecular subtyping of triple-negative breast carcinoma. Methods. Tissue microarrays from 122 surgical specimens of triple-negative breast carcinoma patients and immunohistochemical staining for CK5/6, epidermal growth factor receptor, claudin 3, claudin 4, claudin 7, E-cadherin, androgen receptor, and gamma-glutamyltransferase 1 were used to classify triple-negative breast carcinoma as follows: basal-like type, molecular apocrine type, claudin low type, mixed type and null type. In addition, immunohistochemical staining for metabolism-related proteins such as c-myc, insulin-like growth factor (g)-1, hypoxia-inducible factor 1-1α, glucose transporter 1, carbonic anhydrase IX antibody, macrophage migration inhibitory factor, and pyruvate dehydrogenase kinase 1 was used to compare the differences according to molecular subtype and clinicopathological factors. Results. The basal-like type showed the highest proportion of high glucose transporter 1 expression (P = 0.049) and carbonic anhydrase IX antibody expression (P = 0.008). Hypoxia-inducible factor 1-1α expression was associated with lymph node metastasis (P = 0.001) and central fibrotic zone (P = 0.012), and high glucose transporter 1 expression was related to high histologic grade (P = 0.007), cytokeratin 5/6 positivity (P = 0.002), and central fibrotic zone (P = 0.017). Finally, carbonic anhydrase IX antibody was associated with cytokeratin 5/6 positivity (P = 0.001) and central fibrotic zone (P = 0.048). Conclusions. Our study revealed the different characteristics of cancer cell metabolism according to the molecular subtypes of triple-negative breast carcinoma. Among them, basal-like type was the most glycolytic and acid-resistant phenotype.