Department of Medical and Biological Sciences, Institution of Anatomic Pathology, Azienda Ospedaliero Universitaria S. Maria della Misericordia, Piazzale S. Maria della Misericordia, Udine 33100, Italy.
Virchows Arch. 2013 Jul;463(1):7-15. doi: 10.1007/s00428-013-1440-2. Epub 2013 Jun 19.
The one-step nucleic acid amplification (OSNA) method is an increasingly used procedure for intraoperative analysis of sentinel lymph node (SLN) status in breast cancer patients. It measures cytokeratin19 (CK19) mRNA copy numbers in homogenized samples of SLN; CK19 has been chosen for identifying node metastasis because most breast cancers express this molecule. However, to avoid false-negative OSNA results, testing the preoperative needle core biopsy (NCB) of breast carcinomas for CK19 by immunohistochemistry (IHC) has been recommended. This procedure relies on the assumption that protein expression is strictly related to mRNA expression. We developed this study to evaluate if IHC gives similar result to the molecular assay. In a series of breast cancer patients with axillary metastasis, corresponding surgically resected tumor and metastatic lymph node specimens have been tested for CK19 protein by IHC and for CK19 mRNA by real-time PCR; furthermore, CK19 immunostaining has been performed in NCBs when available. Statistical analysis revealed that (1) the immunohistochemical evaluation of CK19 in NCB is a reliable test, reflecting protein expression in the whole tumor and in the metastatic lymph node; (2) there is no correlation between CK19 protein expression and CK19 RNA level neither within the primary breast cancer nor within the metastatic node; moreover, no correlation as well has been found between protein expression in NCB and mRNA level in metastatic lymph nodes. Thus, our results suggest that there is no evidence-based reason to stain every NCB for CK19 before performing OSNA in patients with breast cancer.
一步法核酸扩增 (OSNA) 方法是一种越来越多地用于分析乳腺癌患者前哨淋巴结 (SLN) 状态的术中分析方法。它测量 SLN 匀浆样本中细胞角蛋白 19 (CK19) mRNA 拷贝数；选择 CK19 来识别淋巴结转移，是因为大多数乳腺癌表达这种分子。然而，为了避免 OSNA 结果出现假阴性，建议对乳腺癌的术前针芯活检 (NCB) 进行 CK19 的免疫组织化学 (IHC) 检测。该程序依赖于这样一个假设，即蛋白质表达与 mRNA 表达严格相关。我们开展这项研究是为了评估 IHC 是否能得到与分子检测相似的结果。在一系列腋窝转移的乳腺癌患者中，对相应的手术切除肿瘤和转移性淋巴结标本进行了 CK19 蛋白的免疫组织化学和 CK19 mRNA 的实时 PCR 检测；此外，在有 NCB 时，还进行了 CK19 免疫染色。统计分析显示：(1) NCB 中 CK19 的免疫组织化学评估是一种可靠的检测方法，反映了整个肿瘤和转移性淋巴结中的蛋白表达；(2) 在原发性乳腺癌和转移性淋巴结中，CK19 蛋白表达与 CK19 RNA 水平之间均无相关性；此外，在 NCB 中的蛋白表达与转移性淋巴结中的 mRNA 水平之间也未发现相关性。因此，我们的结果表明，在对乳腺癌患者进行 OSNA 之前，没有基于证据的理由对每一个 NCB 进行 CK19 染色。
