Expression of angiopoietin-like 4 and tenascin C but not cathepsin C mRNA predicts prognosis of oral tongue squamous cell carcinoma.

Analysis of gene expression using RNA from the paraffin-embedded tissues is becoming an important way to study cancer pathogenesis. In this article, total RNA was extracted from tissue of 158 cases of paraffin-embedded tongue cancer, and expression of angiopoietin-like 4, tenascin-C and cathepsin-C were detected by real-time reverse transcriptase-polymerase chain reaction (RT-PCR). Our results demonstrated that high expression level of angiopoietin-like 4 or tenascin-C was predictive of poor prognosis of tongue cancer patients (p = 0.024 and p = 0.011, respectively), especially when expression levels of both genes were concomitantly high (p = 0.001). Additionally, high expression of angiopoietin-like 4 and tenascin-C, or concomitant high expression of angiopoietin-like 4 and tenascin-C were independent prognostic factors of poor survival in patients with tongue cancer. These results suggest that the improved method of RNA extraction is suitable for analysing gene expression of paraffin-embedded solid tumours. Angiopoietin-like and tenascin-C, especially the combination of angiopoietin-like 4 and tenascin-C, are useful for predicting the prognosis of the patients with tongue cancer, independent of lymph node metastasis status.