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

One-Step Nucleic Acid Amplification System in Comparison to the Intraoperative Frozen Section and Definitive Histological Examination Among Breast Cancer Patients: A Retrospective Survival Study

Simple Summary

Implementing intraoperative assessment of sentinel lymph nodes by one-step nucleic acid amplification in early breast cancer can reduce the surgical burden to the patient and the costs to the health system. However, only limited data are available in terms of long-term disease-free survival and overall survival. Therefore, this study aims to compare disease-free survival and overall survival between one-step nucleic acid amplification, frozen section, and definitive histology. These results could impact the healthcare community, adding further proof to the body of evidence supporting the broader adoption of this innovative technology that enables a safe reduction in patient surgical burden and healthcare costs.

Background

The one-step nucleic acid amplification (OSNA) system is a novel molecular technique, which consents to quick intraoperative detection of sentinel lymph node metastases by the amplification of cytokeratin 19 mRNA. Our study aims to evaluate the OSNA method in comparison with frozen section (FS) and definitive histological examination of the sentinel lymph node biopsy among early breast cancer patients considering disease-free survival (DFS) and overall survival (OS).

Methods

In this study, we included all women who underwent sentinel lymph node biopsy (SLNB) for breast cancers classified as TNM stage I and II in our center between January 2005 and January 2017, and the follow-up was collected up to January 2019. We divided patients among three groups based on SLNB evaluation: definitive histological examination, intra-operative FS, or OSNA.

Results

We included 2412 SLNBs: 727 by definitive histological examination, 697 by FS, and 988 by OSNA. Isolated tumor cells were found in 2.32% of cases, micrometastasis in 9.12%, and macrometastases in 13.64%. Surgical procedure duration was significantly shorter in OSNA than in FS (42.1 minutes ±5.1 vs. 70.1 minutes ±10.5, p <0.05). No significant differences have been observed among the three groups regarding OS, DSF, cumulative local, or distant metastases. In particular 5-year DFS was 96.38% in definitive histology (95% C.I. 95.02-97.75%), 96.37% in FS (95% C.I. 94.98-97.78%), and 96.51% in OSNA group (95% C.I. 95.32-97.72%).

Conclusions

No difference in OS and DFS was found comparing OSNA, FS, and definitive histology. Furthermore, reduced operative time was found in the OSNA group.

Intraoperative prediction of the two axillary lymph node macrometastases threshold in patients with breast cancer using a one-step nucleic acid cytokeratin-19 amplification assay

The aim of the present study was to assess the sensitivity, specificity and practicality of using a one-step nucleic acid amplification (OSNA) assay during breast cancer staging surgery to predict and discriminate between at least 2 involved nodes and more than 2 involved nodes and facilitate the decision to provide axillary conservation in the presence of a low total axillary node tumour burden. A total of 700 consecutive patients, not treated with neo-adjuvant chemotherapy, received intraoperative sentinel lymph node (SLN) analysis using OSNA for cT1-T3 cN0 invasive breast cancer. Patients with at least one macrometastasis on whole-node SLN analysis underwent axillary lymph node dissection (ALND). The total tumour load (TTL) of the macrometastatic SLN sample was compared with the non-sentinel lymph node (NSLN) status of the ALND specimen using routine histological assessment. In total, 122/683 patients (17.9%) were found to have an OSNA TTL indicative of macrometastasis. In addition, 45/122 (37%) patients had NSLN metastases on ALND with a total positive lymph node burden exceeding the American College of Surgeons Oncology Group Z0011 trial threshold of two macrometastatic nodes. The TTL negative predictive value was 0.975 [95% confidence interval (CI), 0.962-0.988]. The area under the curve for the receiver operating characteristic curve was 0.86 (95% CI, 0.81-0.91), indicating that SLN TTL was associated with the prediction (and partitioning) of total axillary disease burden. OSNA identifies a TTL threshold value where, in the presence of involved SLNs, ALND may be avoided. This technique offers objective confidence in adopting conservative management of the axilla in patients with SLN macrometastases.

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

HER2 is a receptor tyrosine kinase and its upregulation via activating mutations or amplification has been identified in some malignant tumors, including lung cancers. Because HER2 can be a therapeutic target in HER2-driven malignancies, it is important to understand the molecular mechanisms of HER2 activation. In the current study, we identified that cytokeratin 19 (KRT19) binds to HER2 at the inside face of plasma membrane. HER2 and KRT19, which were concurrently introduced to a human embryonic kidney 293 T cells, revealed an association with each other and resulted in phosphorylation of HER2 with the subsequent activation of a downstream Erk-associated pathway. A binding assay revealed that both the NH2-terminal head domain of KRT19 and the COOH-terminal domain of HER2 were essential for their binding. To investigate the impact of the interaction between HER2 and KRT19 in lung cancer, we examined their expressions and localizations in lung cancers. We found that KRT19 was highly expressed in HER2-positive lung cancer cells, and KRT19 and HER2 were co-localized at the cell membrane. In conclusion, we found that KRT19 intracellularly binds to HER2, playing a critical role in HER2 activation.

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

Sentinel lymph node (SLN) examination is a standard in breast cancer patients, with several methods employed along its 20 years history, the last one represented by one-step nucleic acid amplification (OSNA). The latter is a intra-operative molecular assay searching for CK19 mRNA as a surrogate of metastatic cells. Our 3 years experience with OSNA (1122 patients) showed results overlapping those recorded in the same institution with a morphological evaluation (930 patients) of SLN. In detail, the data of OSNA were almost identical to those observed with standard post-operative procedure in terms of patients with positive SLN (30%) and micrometastatic/macrometastatic involvement of SLN (respectively, 38–45 and 62–55%). By contrast, when OSNA was compared to the standard intraoperatory procedure, it was superior in terms of accuracy, prompting the use of this molecular assay as a very valid, and reproducible for intra-operative evaluation of SLN. Further possibilities prompting the use of OSNA range from adhesion to quality control programs, saving of medical time, ability to predict, during surgery, additional nodal metastasis, and molecular bio-banking.

Clinical usefulness of one-step nucleic acid amplification assay in the new era of sentinel lymph node biopsy for breast cancer

SUMMARY 

According to the results of the ACOSOG Z0011 trial and IBCSG trial 23-01, rapid intraoperative examinations of the sentinel lymph nodes (SLN) are needed in only a limited number of breast cancer patients, including those with more than three sentinel nodes or who undergo mastectomy. In this new era of SLN biopsies, one-step nucleic acid amplification assay is a promising method for accurately assessing metastasis in the whole SLN, and which help to accurately select patients requiring axillary dissection and reliably evaluate the risk of recurrence. One-step nucleic acid amplification assay may therefore be an alternative to conventional pathology in detecting metastasis in the SLNs, when used for both intraoperative and postoperative examinations.

Surgery in the era of the 'omics revolution

BACKGROUND

Surgery is entering a new phase with the revolution in genomic technology. Cheap, mass access to next-generation sequencing is now allowing the analysis of entire human genomes at the DNA and RNA level. These data sets are being used increasingly to identify the molecular differences that underlie common surgical diseases, and enable them to be stratified for patient benefit.

METHODS

This article reviews the recent developments in the molecular biology of colorectal, oesophagogastric and breast cancer.

RESULTS

The review specifically covers developments in genetic predisposition, next-generation sequencing studies, biomarkers for stratification, prognosis and treatment, and other 'omics technologies such as metabolomics and proteomics.

CONCLUSION

There are unique opportunities over the next decade to change the management of surgical disease radically, using these technologies. The directions that this may take are highlighted, including future advances such as the 100,000 Genomes Project.