A. Dobriyan

Cancer-associated fibroblasts and epithelial-mesenchymal transition in metastatic oral tongue squamous cell carcinoma

We examined cancer‐associated fibroblasts (CAFs) and a panel of immunohistochemical markers of epithelial‐mesenchymal transition (EMT) in 19 pair‐matched oral tongue squamous cell carcinoma (SCC) and metastatic tumors to regional lymph nodes (RLNs). α‐Smooth muscle actin (α‐SMA) was studied to identify CAFs. EMT was studied with syndecan‐1, Cadherin‐11, fibroblast‐specific protein (FSP)‐1, secreted protein acidic and rich in cysteine (SPARC) and Twist. Triple immunostaining in RLNs was used to highlight the carcinoma cells (E‐cadherin and Ki‐67) and their relationship to the CAFs (α‐SMA). We found that metastatic RLNs hosted CAFs similarly as in pair‐matched primary tumors. Expression of EMT markers is common in both primary and metastatic tumors. We demonstrate that metastatic carcinoma cells (Ki‐67 positive) downregulate E‐cadherin expression at the periphery of cancer islands, where they are in direct contact with CAFs. The supporting connective tissue microenvironment also commonly expresses syndecan‐1, Cadherin‐11, FSP‐1, and SPARC. In conclusion, CAFs are common to both primary and metastatic SCC. We hypothesize that CAFs not only promote tumor invasion but also facilitate metastases, either by cometastasizing and/or being recruited to lymph nodes. Evidence of EMT is common within primary tumors and metastatic SCC and may be further modulated by CAFs.

Tumor-host histopathologic variables, stromal myofibroblasts and risk score, are significantly associated with recurrent disease in tongue cancer

Margin status, a major prognostic parameter in oral cancer, was analyzed vis‐à‐vis the histopathologic parameters of risk scores and stromal myofibroblasts. Specimens of tongue carcinoma (n = 50) were submitted to a risk score assignment consisting of the worst pattern of invasion, lymphocytic infiltration, and perineural invasion. Frequency of stromal myofibroblasts (alpha‐smooth muscle actin stain) was assessed. A triple immunostaining assay with E‐cadherin, Ki‐67 and alpha‐smooth muscle actin was used to identify carcinoma cells undergoing epithelial–mesenchymal transition. Margins were considered ‘clean’ if the tumor was ≥5 mm away from them. Patients ≤60 years were considered as ‘young’. Kaplan–Meier survival analysis with univariate and Cox multivariate regression model with stepwise forward selection, and Fisher’s exact tests were used. Abundant myofibroblasts were found in 27 (54%) cases. Carcinoma cells devoid of E‐cadherin but amalgamated with the stromal myofibroblasts were identified in 18 (36%) cases. Local recurrence and overall survival were negatively influenced by abundance of stromal myofibroblasts (P = 0.004 and P = 0.008, respectively). High‐risk scores (P = 0.011), positive margins, and ‘young’ age (P = 0.027, each) had an unfavorable impact on recurrence. Multivariate analysis revealed that only abundance of stromal myofibroblasts had an independent adverse effect on local recurrence (hazard ratio [HR] 4.369; P = 0.014; 95% confidence interval [CI], 1.356–14.074). It seems that abundant stromal myofibroblasts (camouflaging some malignant cells) and high‐risk scores have an unfavorable impact on the risk of recurrence in particular in ‘young’ patients. Therefore, the treatment concept should be adjusted accordingly and target concomitantly the epithelial malignancy and its allied stroma. (Cancer Sci 2009)

Cancer-associated fibroblasts, a parameter of the tumor microenvironment, overcomes carcinoma-associated parameters in the prognosis of patients with mobile tongue cancer

Mobile tongue squamous cell carcinoma (MTSCC) is known for its strong propensity for regional metastasis and poor patient survival despite aggressive treatment, thus calling for new and reliable markers for predicting prognosis and guiding therapeutic management. Towards this end, three classes of markers were investigated: cancer-associated fibroblasts (CAFs; α-SMA positivity) as a representative of the tumor microenvironment, maspin (mammary serine protease inhibitor) as a tumor marker likely to be modulated by factors within the tumor microenvironment, and DNA content and Ki-67 labeling index as inbuilt tumor markers in 128 cases of MTSCC using immunohistochemistry and image cytometry. Of these markers, only CAF density was independently and relatively strongly associated with elevated mortality from MTSCC. The hazard ratio in the CAF-rich type of tumor microenvironment was 4.85 (95% CI 1.41-16.6, versus the CAF-poor) when adjusted by proportional hazards modeling for the center where the patient was managed, gender, tumor stage, presence of neck metastasis and age at diagnosis. CAF density was unrelated to non-MTSSC mortality. Given the strong association between increased CAF density and higher mortality in MTSCC, routine assessment of CAF density for disease course prognosis and inclusion as an integral part of treatment protocols are recommended.

Key architectural changes in tumor-negative lymph nodes from metastatic-free oral cancer patients are valuable prognostic factors

Regional lymph node (LN) metastasis in oral cancer patients is the most significant grave prognostic factor. We evaluated the relationship between clinical outcomes and different histopathological changes in tumor-negative LNs (LN0) selected from neck dissections without metastatic disease (pN0). A total of 435 LN0 selected from pN0 neck dissections (up to three nodes in each level) were scored for histopathological parameters of LN areas, capsule thickness, subcapsular and medullary sinus ectasia, lobular architecture and percent of cortical reactive follicles. These were compared to 328 LN0 selected from neck dissections with metastases (pN+) after exclusion of metastatic LNs. Data were presented by maximum scores of each parameter in I–III (close) and in IV–V (distant) levels. Limited data from level V and regression analyses inferred that the values in level IV represented the worst changes for most patients. Cox proportional hazard regression on each parameter in close and distant levels demonstrated that capsule thickness, number of lobules and percent of reactive follicles were significantly associated with time to death from disease. The higher the change in distant levels, the shorter the time to death, while the higher the change in close levels (given a stable change in distant levels), the longer the time to death. After adjustment for gender, age and location, only the effect of the percent of reactive follicles retained their significant effect. Logistic regression of metastases demonstrated that all parameters except for percent of reactive follicles were significantly associated with risk of metastases, with differences between close and distant levels similar to those found for time to death. After adjustment for gender, age and location, only the area and number of lobes retained their significance. The findings of this study suggested that selective histopathological changes in tumor-negative LNs in metastatic-free patients provide new valuable prognostic parameters.