In this study, we observed that low expression of B2M was a strong prognostic indicator of lymph node metastases regardless of whether the mean expression value of the 15-gene set was used as an internal reference control (AUC=0.85; Table 4), the median expression value of the 15-gene set was used (AUC=0.83), Spint2 was used as a single internal reference gene (AUC=0.87), or classic reference genes such as TBP or UBP were used (AUC=0.79). Here, B2M is linked to metastatic malignant neoplasm in the lymph nodes.