Evaluation of a Direct Reverse Transcription Loop-Mediated Isothermal Amplification Method without RNA Extraction (Direct RT-LAMP) for the Detection of Lymph Node Metastasis in Early Breast Cancer

PURPOSE: Assessing lymph node metastasis, tumor-derived DNA, or tumor-derived RNA has previously been studied in place of immunohistochemical assay. Because a direct reverse transcription loop-mediated isothermal amplification method (direct RT-LAMP) has been previously developed in order to rapidly identify viruses in place of RNA extraction, our team hypothesized that a direct RT-LAMP assay can be employed as a substitute in order to detect tumor involvement of lymph nodes within breast cancer patients. MATERIALS AND METHODS: A total amount of 92 lymph nodes removed across 40 patients possessing breast cancer were collected at Kyungpook National University Chilgok Hospital between the months of November 2015 and February 2016. All samples were then evaluated and contrasted via both a direct RT-LAMP assay and routine histopathologic examination. RESULTS: The sensitivity and specificity of the direct RT-LAMP assay were 85.7% and 100%, respectively. The positive predictive value and negative predictive value were 100% and 94.4%, respectively. CONCLUSION: Direct RT-LAMP assay is capable of facilitating the detection of sentinel lymph node metastasis within breast cancer patients intraoperatively possessing an excellent sensitivity via a cost-effective and time-saving manner.