Expression of metabolism-related proteins in invasive lobular carcinoma: comparison to invasive ductal carcinoma.

The purpose of this study is to investigate the difference in expression of metabolism-related proteins in invasive lobular carcinoma (ILC) compared to those of the invasive ductal carcinoma (IDC). Tissue microarray was manufactured for 114 cases of ILC and 692 cases of IDC. Immunohistochemical stains were performed as follows: glycolysis (Glut-1, hexokinase II, CAIX, MCT4), glutaminolysis (GLS1, GDH, ASCT2), mitochondria (ATP synthase, SDHA, SDHB), and serine/glycine metabolism (PHGDH, PSAT1, PSPH, SHMT1, GLDC) related proteins. Pleomorphic type (n = 12) of ILC revealed higher expression in hexokinase II, SDHB, and GLDC than classic type (n = 102) (p < 0.05). IDC showed a higher expression of glycolysis (Glut-1, CAIX, MCT4), glutaminolysis (GLS1, ASCT2), and serine/glycine metabolism (PSPH, SHMT1, GLDC) related protein than ILC in tumor cells, whereas ILC revealed higher expression in GDH, SDHA, PHGDH, and PSAT1 than IDC in tumor cells (p < 0.05). In addition, IDC demonstrated a higher expression of metabolism-related proteins than ILC in stromal tissue (p < 0.05). In ILC, tumoral GLDC positivity was correlated with higher nuclear grade (p = 0.026) and higher histologic grade (p = 0.026), and tumoral Glut-1 positivity correlated with higher histologic grade (p = 0.026). Additionally, tumoral PSPH positivity showed a significant correlation to ER negativity and PR negativity (p = 0.026). In conclusion, it reveals different expression patterns of metabolism-related proteins between IDC and ILC.