One-step nucleic acid amplification (OSNA) for intraoperative evaluation of sentinel lymph node status in breast cancer: a comparative study between CK19 protein expression and CK19 mRNA level in primary tumors and lymph node metastasis

Abstract

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.

Evaluation of Sentinel Lymph Node Intraoperative Touch Imprint Cytology in Breast Cancer Surgery

“…Touch imprint cytology (TIC), frozen section (FS) analysis and onestep nucleic-acid amplification (OSNA) represent the most common techniques available to intraoperatively detect breast cancer axillary sentinel lymph node (SLN) metastasis [8,9]. However, recent studies have stated that TIC is not anymore, a useful technique to detect SLN metastasis in breast cancer [17,18].…”

“…The most common ones include frozen section (FS), touch imprint cytology (TIC) [8] and one-step nucleicacid amplification (OSNA) [9].…”

Interaction of cytokeratin 19 head domain and HER2 in the cytoplasm leads to activation of HER2-Erk pathway

“…The major cellular functions of cytokeratins are mechanical support, cytoarchitecture, cell migration, and signal modulation26. Among keratins, the KRT19 is the smallest member of the type I keratin family and is known as a tumor marker in several kinds of malignancies12131415161718. Regarding the function of KRT19 in cancers, the expression of KRT19 might contribute to the invasiveness of hepatocellular carcinoma (HCC)27.…”

“…In the course of identifying novel partner receptor for TD mutant HER2, we found that cytokeratin 19 (KRT19) is bind to wild type HER2 in A549 lung cancer cell line. KRT19, which is a member of the keratin intermediate filament family of proteins, is well known to be generally overexpressed in various cancers121314151617, and its fragment known as CYFRA has been shown to be a tumor marker in some subsets of lung cancers1218. In this study, we determined the binding sites of KRT19 and HER2 and investigated the impact of KRT19 and HER2 interactions in signal transduction pathways to decode their possible roles in oncogenesis.…”

One-Step Nucleic Acid Amplification in Breast Cancer Sentinel Lymph Node: A Single Institutional Experience and a Short Review

“…This possibility was estimated to occur in 2–3% of breast cancer evaluated using immunohistochemistry. However, Pegolo et al (26) showed that cases with negative CK19 immunostaining had a significant CK19 expression at mRNA level. We have also adopted and recommend the use of intra-operative cytological smear before starting an OSNA procedure to avoid false-negative cases.…”