CK19 testing prior to OSNA analysis: To stain or not to stain?

摘要

We read with interest the article by Vilardell et al. [1] where lymph node metastasis was missed in a patient with a cytokeratin-19 (CK19)-negative breast cancer. Sentinel node biopsy (SNB) is currently the standard practice for staging the axilla [2], with one-step nucleic acid amplification (OSNA) becoming more widely accepted [3] and used in clinical practice. OSNA detects metastasis by quantifying the presence of CK19 mRNA, in theory irrespectively whether this is expressed or not. There are limited data regarding the true incidence of CK19-negative tumours. The authors estimate this to be about 3 %, which is probably similar to anecdotal data in our practice.