Desmoglein 1 and 3 as potential markers of occult lymph node metastasis in oral cancer

The majority of oral cancers are oral squamous cell carcinomas (OSCC). The successful management of OSCC depends on early detection, timely intervention, and prevention of distant metastasis. Metastasis is an important aspect of OSCC-related deaths. Diagnosis of cervical lymph node metastasis is an essential requirement for clinical staging and treatment and is now widely accepted as an important factor in the prognosis of OSCCs. Roles of desmosomal cadherins desmoglein 1 (DSG1) and desmoglein 3 (DSG3) have been extensively studied and DSG3 is known to be a squamous-specific protein marker that is expressed specifically in the positive lymph nodes, and hence a potential marker for detecting occult lymph nodes, however, no conclusive evidence is established. The objective of this study was to assess DSG1 and DSG3 as potential biomarkers of lymph node metastasis.

A total of 50 archival lymph node blocks, both positive and negative neck nodes of the patients treated for OSCC, were used for the assessment of DSG1 and 3 expressions by immunohistochemistry (IHC) following their histopathological examination. The assessment of IHC staining was conducted by two independent maxillofacial pathologists as per the grading criteria in all the lymph node sections.

A total number of 88 nodes were assessed, of which 27 were positive on histopathological assessment. DSG1 and DSG3 positivity were noted and varied between 11.4-12.5% and between 20.5-22.7% of positive nodes, respectively, between the observers. Cronbach's alpha was calculated for interobserver reliability for positive identification of metastatic lymph nodes. Area under curve (AUC) values for DSG1 were 0.478 and 0.02 for DSG3, and not so statistically significant value for DSG1 was obtained (P > 0.05) compared to DSG3 (P = 0.000).

Current study results do not confirm the roles of DSG1 and 3 as potential markers for occult lymph node metastasis, and hence, the reliability of their roles may require further studies along with other markers of lymph node metastasis. Even though overexpression of DSG3 and partial expression of DSG1 in OSCC is seen, further studies may be required to confirm them either as a diagnostic or prognostic marker which can be useful for future management in cases of radical neck dissections.