Investigating Biomarkers in Primary Tumors and Lymph Node Metastases in Tongue Squamous Cell Carcinoma: An Immunohistochemical Perspective

This study aimed to gain insight into cancer progression and the metastatic process by analyzing protein expression patterns in primary, metastatic, and nonmetastatic tongue squamous cell carcinoma (TSCC), with a focus on understanding biomarker changes between primary tumors and lymph node metastases. A total of 60 TSCC biopsy samples, 20 primary metastatic, 20 lymph node metastatic, and 20 nonmetastatic, were immunohistochemically stained to analyze MCM2, CD44, and E-cadherin expression. Expression levels were assessed through immunoreactivity scores, and differences across groups were evaluated using generalized estimating equations (GEE). No significant differences in biomarker expression were observed between primary tumors and their lymph node metastases. However, significant variations were identified in MCM2 and E-cadherin expression across the groups. MCM2 expression was notably lower in lymph node metastases compared with nonmetastatic TSCC ( P = 0.025), and E-cadherin expression was reduced in primary tumors relative to nonmetastatic samples ( P = 0.028). CD44 expression did not show significant variation across the different groups. The results align with the classic model of TSCC metastasis, suggesting biomarker stability between primary and metastatic sites. However, variations in MCM2 and E-cadherin expression between specific groups highlight their potential roles in TSCC progression. Further investigation into additional markers and pathways could offer a more comprehensive understanding of TSCC metastasis and contribute to more precise therapeutic approaches.