Intraoperative Molecular Profiling of Sentinel Lymph Nodes: Diagnostic Value of Mammaglobin and CK19 in Early Breast Cancer

Breast cancer represents a major public health problem worldwide. Despite radical surgery for localized disease, a substantial proportion of patients experience disease recurrence. The aim of this study was to evaluate the expression of the mammaglobin and CK19 genes in sentinel lymph node biopsies from patients with early breast cancer. This descriptive study included 301 sentinel lymph node biopsies from patients with stage I–II breast cancer treated at the San Carlos Clinical Hospital in Madrid, Spain. Metastases were identified using conventional histopathology (H&E), immunohistochemistry (IHC), and molecular detection of mammaglobin and CK19 using PCR-based methods. Associations between variables were assessed using Fisher’s exact test with a 95% confidence level. Statistical analyses were performed using STATA 12.0. The predictive value for metastatic involvement was 12.29% for CK19 and 16.61% for mammaglobin, increasing to 19.27% when conventional staining was combined with immunohistochemistry. The overall sensitivity was 68.9%, and the specificity was 93.42%. Mammaglobin showed slightly better diagnostic performance than CK19, and the combined molecular detection of both genes improved diagnostic accuracy when compared with individual markers. Intraoperative molecular evaluation of sentinel lymph nodes using mammaglobin and CK19 is comparable to conventional histopathological assessment combined with immunohistochemistry. The combined RT-PCR detection of both genes improves diagnostic performance and represents a clinically useful complementary tool for the detection of metastatic involvement in early breast cancer.