Quantitative expression study of four cytokeratins and p63 in squamous cell carcinoma of the tongue: suitability for sentinel node navigation surgery using one-step nucleic acid amplification.

Aims: Sentinel node navigation surgery (SNNS) is currently considered to provide better staging of regional metastasis. For rapid and accurate sentinel lymph node analysis, one-step nucleic acid amplification using cytokeratin 19 (CK19) has been applied, particularly in breast cancer. On the other hand, additional quantitative reverse transcription PCR targets containing cytokeratins have been reported recently in head and neck cancer. In this report, CK19 and p63 were immunohistochemically examined in primary tumours for use as molecular markers and were compared with cytokeratin 903 (CK903), cytokeratin 8/18 (CK8/18) and cytokeratin (AE1/AE3), which are used in diagnostic immunohistochemistry for head and neck squamous cell carcinoma.

Methods: The study reviewed 17 patients with T1/T2, N0 (UICC) oral squamous cell carcinoma of the tongue who were treated surgically at Kyorin University Hospital between 2002 and 2009. The intensity and proportion of tumour cells stained for CK19, CK903, p63, CK8/18 and AE1/AE3 were evaluated.

Results: CK19 and CK8/18 staining in cytoplasm was patchy among carcinoma cells, indicating weak expression. Staining proportion for p63, CK903 and AE1/AE3 was greater than for CK19 and CK8/18, although staining intensity for CK903 was weaker than for p63 and AE1/AE3. The difference in total score between CK19 and CK8/18 staining and p63, CK903 and AE1/AE3 staining was statistically significant (p<0.001). p63 and AE1/AE3 may be better markers than CK903, CK19 and CK8/18.

Conclusions: This suggests that p63 is of clinical utility in SNNS and that CK19 is unsuitable for early tongue carcinoma. Further studies are needed before clinical application of these markers.