FNDC5 and metastatic malignant neoplasm in the lymph nodes: As in the case of irisin levels assessed by IHC, we observed higher FNDC5 gene expression in patients without lymph node metastases (mean 9.092 ± SD 1.7; p = 0.0395) compared to subjects with metastases (mean 3.679 ± SD 0.9; Figure 7a,b).