Real-Time RT-PCR for the Diagnosis of Sentinel Lymph Node Metastasis in Breast Cancer (Feature Article) (Reverse Transcriptase Polymerase Chain Reaction) (Report‪)‬

Introduction Sentinel lymph node (SLN) biopsy has become well established as the standard for axillary node staging in breast cancer [1-3]. The sentinel lymph node should be carefully and intensely examined for this procedure to be most accurate. The previous staging system counted all nodal metastases as positive regardless of the size of the metastatic deposit. In the sixth edition of the American Joint Committee on Cancer (AJCC) staging system for breast cancer, by contrast, nodal stage is partly defined by the size of the micrometastasis [4]. Nodal metastases larger than 2.0 mm in diameter are now counted as pN1 or greater, depending on the number of nodes with metastases. Nodal metastatic deposits 0.21-2.0 mm in diameter are now labelled as pN1mi (micrometastases). Clusters of malignant cells 0.2 mm in diameter or smaller that are seen in nodes are now defined as pN0. If techniques such as immunohistochemistry or polymerase chain reaction (PCR) are used to detect tumour cells, then a descriptor for the method can be so indicated as pN0 (i+) or pN0 (mol+), respectively.