Cytokeratin 19 expression in early oral squamous cell carcinoma and their metastasis: Inadequate biomarker for one-step nucleic acid amplification implementation in sentinel lymph node biopsy procedure.

Abstract

Intraoperative analysis of lymph nodes during a sentinel lymph node biopsy (SLNB) procedure could result in one-step surgery for early oral squamous cell carcinoma (OSCC) with an occult nodal metastasis. One-step nucleic acid amplification rapidly detects cytokeratin 19 (CK19) RNA with high accuracy. Sensitivity and specificity of CK19 expression in OSCC was evaluated. Immunohistochemical CK19 expression was done in 207 patients with OSCC with 65 cases of paired nodal metastases. CK19 was expressed in 65% of all OSCC and even less in early OSCC (56%), with poor correlation between primary tumor and (occult) nodal metastasis. Furthermore, ectopic glandular tissue in close proximity of lymph nodes showed strong CK19 expression. CK19 lacks both sensitivity and specificity as a biomarker for nodal metastasis in OSCC, which questions the suitability for CK19-based one-step nucleic acid amplification in SLNB procedures. Therefore, future studies should focus on other biomarkers, because the concept of fast intraoperative diagnostics during SLNB remains attractive.