Localization and characterization of lymphatic vessels in oral and cervical squamous cell carcinoma

Lymph node metastasis is considered a factor in determining the prognosis of squamous cell carcinoma (SCC). Both oral and cervical SCC tumor cells prefer lymph vessels as the route of metastasis. D2-40 is a specific marker of lymphatic endothelial cells. This study clarifies the distribution and characteristics of lymphatic vessels in oral and cervical SCCs. Immunohistochemistry was performed in 20 oral and 20 cervical SCCs (10 non-metastatic and 10 metastatic to lymph nodes) using D2-40, CD31, CD34, CD105 and double staining with D2-40 and keratin. Lymphatic vessel density (LVD) was also determined morphologically. Results showed that lymphatic vessels in both types of SCCs were distributed mainly at the superficial region beneath the epithelium. The LVD in each tumor was significantly higher compared to the corresponding normal mucosa. Moreover, the LVD in lymph node metastasis in each tumor was significantly higher compared to their non-metastatic counterparts. Cancer cell invasion was observed in the lymphatic vessels suggesting the existence of lymph node involvement during metastasis. The new lymphatic vessels that proliferated around the cancer nests in both SCCs have endothelial cell characteristics inferred to be associated with early lymphatic development and initial dissemination of cancer cells.