The OSNA assay (Sysmex, Kobe, Japan) analyzes the whole SLN through a semi-quantitative result based on the detection and real-time reverse transcription-loop-mediated isothermal amplification (RT-LAMP) of cytokeratin 19 (CK19) mRNA, and provides accurate intraoperative detection of lymph node metastases [6–11]. Here, KRT19 is linked to metastatic malignant neoplasm in the lymph nodes.