Tumor-associated carbonic anhydrase XII is linked to the growth of primary oral squamous cell carcinoma and its poor prognosis

The pattern of protein expression in tumors is under the influence of nutrient stress, hypoxia, and low pH, which determines the survival of neoplastic cells and the development of tumors. Carbonic anhydrase (CA) XII is a transmembrane enzyme that catalyzes the reversible hydration of cell-generated carbon dioxide into protons and bicarbonate. Hypoxic conditions activate its transcription and translation, and enhanced expression is often present in several types of tumors. However, CA XII expression in oral squamous cell carcinoma (OSCC) and its correlation with patients' prognosis have not been investigated so far. In this study, we detected the expression of CA XII in 264 patients with OSCC using tissue microarrays (TMAs), and evaluated its correlation with clinicopathologic factors and disease prognosis. CA XII expression was present in 185/264 (70%) cases and was associated with more-advanced clinical stages (p = 0.003), a larger tumor size (p <0.001), and postoperative recurrence (p = 0.047), but was not associated with positive lymph node metastasis or distal metastasis. Importantly, CA XII expression was correlated with a poorer patient prognosis in a univariate (p = 0.034, log-rank test) survival analysis. According to our results, the expression of CA XII in OSCC samples can predict the progression of OSCC and survival of OSCC patients.