Expression of pyruvate kinase isoform M2 and its relationship with BRAF mutation in papillary thyroid carcinoma

Objective: To explore the relationship between PKM2 (M2 isoform of pyruvate kinase) expression and the clinicopathological features and BRAF (B-type Raf kinase) gene mutation in human PTC (papillary thyroid carcinoma). Methods: The expressions of PKM2 protein in 82 human PTC tissue samples, 40 human normal thyroid tissue samples and 20 human nodular goiter tissue samples were detected by immunohistochemistry. The BRAF gene mutation status in PTC tissues was examined using PCR (polymerase chain reaction) amplication and direct sequencing. Results: The expression level of PKM2 protein varied in 91.5% (75 of 82) of PTC tissues. Otherwise, there was no expression of PKM2 in normal thyroid tissues and nodular goiter tissues. The expression of PKM2 was associated with T staging and lymphatic metastasis (P < 0.05). The positive rates of PKM2 expression in 46 PTC tissue samples carrying a BRAF mutation and 36 PTC tissue samples carrying wild type BRAF were 100.0% (46/46) and 86.1 % (31/36), respectively (P < 0.05). Conclusion: This study demonstrated that the over-expression of PKM2 is associated with the aggressiveness of PTC and BRAF gene mutation status. DOI:10.3781/j.issn.1000-7431.2013.04.010