Podoplanin is an Efficient Predictor of Neck Lymph Node Metastasis in Tongue Squamous Cell Carcinoma with Low Tumor Budding Grade

The current study investigated the efficacy of podoplanin expression in tumor budding cells as a predictor of neck lymph node metastasis (NLM) in patients with tongue squamous cell carcinoma (SCC) of low tumor budding grade (TBG). A total of 99 patients with early T-stage tongue SCC of any clinical N status who received the initial curative treatment were enrolled. The association between podoplanin expression and NLM was immunohistochemically analyzed, with a focus on tongue SCC with low TBG. The disease-specific survival (DSS) rate was 77% at 5 years, and a significant difference was observed between the NLM-positive and NLM-negative groups, and between the low (n=77) and high (n=22) TBG groups. In the low TBG group, there was a significant difference in DSS between the NLM-positive and NLM-negative groups. The multivariate analysis showed that lymphatic vessel invasion (ly) [odds ratio (OR)=11.5, 95% confidence interval (CI): 1.50-87.6; P=0.02] and podoplanin expression (OR=7.07, 95% CI: 1.80-27.7; P=0.005) were significantly correlated with NLM. Furthermore, negative predictive values (NPV) of ly and podoplanin expression for NLM were 75% and 88%, respectively. Considering the balance of stratification case number adding to ratio, NLM-negative prediction by podoplanin was more significant than that by ly for the low TBG group. The results of the present study demonstrated that podoplanin expression in tumor budding is an independent and efficient predictor of NLM in the tongue SCC with low TBG. The low TBG and podoplanin-negative cases may be candidates for the wait and watch policy, therefore, reducing inappropriate elective neck lymph node dissections.