Some scholars have established some prediction models to predict NSLN metastasis in SLN positive breast cancer patients, such as Memorial Sloan-Kettering Cancer Center model (United States),[31] and Stanford University model.[32] In addition, some scholars established NSLN metastasis predictive mode using 1-step nucleic acid amplification technique to evaluate CK19 mRNA copy number in SLN. This evidence concerns the gene KRT19 and breast carcinoma.