The pattern and spread of invasion can predict late cervical lymph node metastasis in early tongue squamous cell carcinoma.

To determine the predictive indexes of late cervical lymph node metastasis in early tongue squamous cell carcinoma (TSCC). We retrospectively analyzed the cases of 25 patients with stage I/II TSCC who had undergone surgical treatment without elective neck dissection. We evaluated the relationships between clinicopathologic factors and the occurrence of late cervical lymph node metastasis. Of the 25 cases, metastasis to the cervical lymph nodes was observed in nine cases (36.0%). The clinicopathological factors associated with late cervical lymph node metastasis were the mode of invasion (MOI, p = 0.032), depth of invasion (DOI, p = 0.004), and perineural invasion (PNI, p = 0.040). A multivariate analysis revealed that only the DOI was an independent predictor of late cervical lymph node metastasis. The combination of the DOI and MOI or the PNI and MOI was significantly correlated with late cervical lymph node metastasis (p = 0.004 and p = 0.012, respectively). Our findings suggest that combinations of the MOI, DOI, and PNI could be used as an index for predicting late cervical lymph node metastasis in early TSCC.

Tumour: Fibroblast Interactions Promote Invadopodia-Mediated Migration and Invasion in Oral Squamous Cell Carcinoma.

Objectives: In the progression of cancer, interactions between cancer cells and cancer-associated fibroblasts (CAFs) play important roles. Cancer cell invasion is facilitated by filamentous actin (F-actin)-rich membrane protrusions called invadopodia, and the relationship between CAFs and invadopodia has been unclear. We used oral squamous cell carcinoma (OSCC) to investigate CAFs' effects on the formation of invadopodia, and we assessed the expressions of invadopodia markers and CAF markers ex vivo and their relationship with clinical parameters and survival. Materials and Methods: We examined the effect of culture with normal oral fibroblast (NOF)-derived and CAF-derived conditioned medium on the migration and invasion of two OSCC-derived cell lines using Transwells in the absence/presence of Matrigel. Immunoblotting and immunocytochemistry were conducted to assess the expressions of the invadopodia markers tyrosine kinase substrate 5 (Tks5) and membrane type 1 matrix metalloproteinase (MT1-MMP). We also used immunohistochemistry to examine patients with OSCC for an evaluation of the relationship between the CAF marker alpha smooth muscle actin (αSMA) and the expression of Tks5. The patients' survival was also assessed. Results: Compared to the use of culture medium alone, NOF-CM and CAF-CM both significantly increased the OSCC cells' migration and invasion (p < 0.05), and they significantly increased the expressions of both Tks5 and MT1-MMP. After the depletion of Tks5, the OSCC cells' migration and invasion abilities decreased. The expression of Tks5 and that of αSMA were correlated with poor survival, and a high expression of both markers was associated with an especially poor prognosis. Conclusions: These results indicate that the formation of invadopodia is (i) important for OSCC cells' migration and invasion and (ii) regulated by the interaction of OSCC cells and stromal fibroblasts.

Caveolin-1 Expression at Metastatic Lymph Nodes Predicts Unfavorable Outcome in Patients with Oral Squamous Cell Carcinoma.

We evaluated the clinical and prognostic value of the protein expression of caveolin-1 (CAV1) and p16 at the primary site and metastatic lymph nodes of oral squamous cell carcinoma (OSCC). Primary site specimens from 80 OSCC cases were randomly selected and lymph node specimens from 15 preserved metastatic lymph nodes from among those patients were selected for examination. We evaluated the CAV1 and p16 expression at both the primary site and metastatic lymph nodes, and analyzed the patients' clinicopathological data in relation to CAV1 and p16 expression. Our analysis revealed significant positive correlations between CAV1 expression at the primary site and pathological metastasis, cell differentiation, and mode of invasion (p = 0.019, p = 0.002, p = 0.015, respectively), but p16 expression was not associated with any clinicopathological factors. Patients with high CAV1 expression at the primary sites showed significantly worse prognoses than those with low or negative CAV1 expression (p = 0.002), and multivariate analysis showed that the T classification and CAV1 expression were independent OSCC prognostic factors. CAV1 expression was also present in the metastatic lymph nodes of the OSCC cases with particularly poor differentiation and high invasive grade, and patients with CAV1-positive metastatic lymph nodes showed significantly worse prognoses than those with CAV1-negative metastatic lymph nodes (p = 0.018). CAV1 may activate metastaticity and the invasive capacity of OSCC cells. CAV1 expression, particularly at metastatic lymph nodes, predicts a worse outcome for OSCC, suggesting that CAV1 could be used as a prognostic marker for OSCC.

Focal Adhesion Kinase (FAK) Overexpression and Phosphorylation in Oral Squamous Cell Carcinoma and their Clinicopathological Significance.

Focal adhesion kinase (FAK) is involved in progression of various cancers, and FAK overexpression has been associated with cancer invasion and metastasis. However, the involvement of FAK expression in the clinicopathological malignancy of oral squamous cell carcinoma (OSCC) remains unknown. In addition, there is no consensus regarding the role of p16 expression in OSCC. In this study, the immunohistochemically measured expression of FAK, phosphorylated FAK (FAKpY397) and p16 expressions and their associations with clinicopathological features and 5-year survival rates were examined in surgical samples from 70 patients with primary OSCC. FAK and FAKpY397 were expressed at high levels in 42 cases (60.0%) and 34 cases (48.6%), respectively, and 9 cases (12.9%) were positive for p16. FAK expression was significantly correlated with local recurrence, subsequent metastasis, and the mode of invasion. FAKpY397 expression was significantly correlated with both N classification and the mode of invasion. p16 expression was significantly correlated with clinical stage only. Patients having high expression of FAK, FAKpY397, or both showed significantly worse prognosis, but p16 expression showed no significant relation to prognosis. The results suggested that overexpression and phosphorylation of FAK in OSCC may affect cancer progression, such as local invasion and lymph node metastasis, and thereby contribute to life prognosis.

Clinicopathological Significance of the ET Axis in Human Oral Squamous Cell Carcinoma.

The interaction between cancer cells and the surrounding microenvironment in malignant tumor tissue is known to be closely associated with cancer cell invasion and proliferation. Endothelin (ET) present in the microenvironment surrounding tumors has been reported to play a role in cancer cell invasion and proliferation by binding to receptors on the cell membrane of cancer cells. Here, we immunohistologically detected the expression of ET-1 and its receptor ETAR in oral squamous cell carcinoma (OSCC) and evaluated the association between the expression of each as well as their co-expression (ET-axis expression) and clinicopathological factors. A significant difference was observed between the invasion pattern as a parameter of cancer cell malignancy and the expressions of ET-1 and ETAR. The survival rates were significantly lower among the patients who were strongly positive for ET-1 and the ETAR-positive patients compared to negative patients. There was also a significant difference between ET-axis expression and the degree of histological differentiation and mode of invasion, and the survival rate of the positive cases was significantly lower than that of the negative cases. Our findings suggested that ET-axis assessments are important for assessing the malignancy of cancer cells and predicting the prognoses of OSCC patients.