Novel Biomarkers Aim at Detecting Metastatic Sentinel Lymph Nodes in Breast Cancer

Background: Intra-operative molecular diagnostic assays are currently used for the detection of lymph node metastases. The objective of this study was to find new biomarkers to improve diagnostic accuracy in the detection of metastatic axillary lymph nodes in breast cancer patients. Methods: We applied an absolute quantitative real-time RT-PCR to quantitate the expression of CK19, KLK11, and CLEC3A mRNAs in 79 FFPE SLNs from 35 breast cancer patients. The CK19 was confirmed as a standard biomarker, and the level of expression of selected new markers, KLK11 and CLEC3A, was evaluated in pathologically negative and positive SLNs by using absolute quantitative real-time PCR. Results: The overall concordance of the CK19 gene with pathological results was 92.4% (less than 250 copies) in negative SLNs and 85% in positive SLNs (more than 250 copies). The sensitivity and specificity of CK19, which were detected by real-time PCR, was 85% and 46%, respectively. Our results revealed that lower CLEC3A was associated with more lymph node involvement. We could set a cut-off point for CLEC3A with the sensitivity of 78% and specificity of 60%. Also, the mean KLK11 had a statistically significant reverse correlation with tumor grade (p = 0.017). Higher CK19 levels were related to more tumor invasion (p < 0.0001). Conclusion: Regarding the findings, CLEC3A along with CK19 can be used as a promising marker with high sensitivity and specificity for the detection of metastatic SLN.