Implications of TP-positive CAFs in the Bone Invasion of Oral Squamous Cell Carcinoma.

BACKGROUND/AIM: Cancer-associated fibroblasts (CAFs) have recently been suggested as critical cellular components of bone invasion in oral squamous cell carcinoma (OSCC). However, the underlying molecular mechanisms and subtypes related to their bone-invasive function are unclear. This study investigated the implications of thymidine phosphorylase (TP)-positive CAFs (TP+CAFs) in OSCC bone invasion. MATERIALS AND METHODS: TP expression was determined in 116 patients with OSCC using immunohistochemistry. The influence of TP expression on the biological behavior of CAFs was investigated in vitro. The possible impact of TP+CAFs on bone invasion in OSCC was further evaluated using patient-derived xenograft (PDX) mouse models. RESULTS: In bone-invasive OSCC tissues, TP+CAFs were mainly distributed on the surface of resorbed bone tissue rather than on the tumor side. High levels of TP+CAFs were significantly associated with higher T-stage, bone invasion, and worse overall survival and recurrence-free survival in our study cohort. Recombinant human TP promoted the proliferative and invasive abilities of CAFs and increased matrix metalloproteinase-9 mRNA expression in vitro, related to bone resorption. In the PDX mouse models, TP+CAFs were found in early bone resorption on the surface of resorbed bony tissues. Bone resorption occurred more frequently in the PDX models with TP+CAFs than in those without. CONCLUSION: TP+CAFs were significantly associated with bone invasion and the prognosis of OSCC. This study provides insights into cellular and molecular targets for the early diagnosis and treatment of bone-invasive OSCC.

Implication of TIPE2 Expression on the Malignant Transformation of Oral Leukoplakia.

BACKGROUND/AIM: Identification of biomarkers involved in the malignant transformation of oral leukoplakia (OL) is required for the early diagnosis and management of patients with OL. This study aimed to evaluate the functions of tumor necrosis factor-alpha-induced protein 8-like 2 (TIPE2) expression in the malignant transformation of OL. MATERIALS AND METHODS: The expression levels of TIPE2 and dormant cell markers phospho-ERK and phospho-p38 in a cohort containing 103 surgical specimens from patients with OL were evaluated using immunohistochemistry. The influence of TIPE2 expression on the biological behavior of the immortalized human oral keratinocyte (IHOK) line was investigated in vitro. RESULTS: Increased TIPE2 expression was detected in 40 (38.8%) patients with OL. In a multivariate analysis using clinicopathological variables and TIPE2 expression as cofactors, the presence of dysplasia (p=0.003) and TIPE2 abundance (p=0.019) were identified as independent risk factors for the malignant transformation of OL. Moreover, the in vitro analysis revealed that TIPE2 knockdown can promote the proliferating ability of IHOK; however, the number of apoptotic cells also increased after TIPE2 knockdown in IHOK. Furthermore, TIPE2 expression was significantly associated with phospho-p38 expression, a dormant cell marker, in our cohort (p=0.047). CONCLUSION: TIPE2 expression may contribute to the malignant transformation of OL, and its function may be related to cellular dormancy in OL pathogenesis.

Proteasome Subunit Alpha Type-7 Expression Suppresses Cutaneous Squamous Cell Carcinoma Progression by Inhibiting Cancer-associated Cytokines.

BACKGROUND/AIM: Cutaneous squamous cell carcinoma (cSCC) is a common non-melanoma skin cancer, and its incidence is increasing. Proteasome subunit alpha type-7 (PSMA7) has been found to be aberrantly expressed in several cancers. However, whether it functions as a tumor suppressor or oncogene in the pathogenesis of cancers, particularly cSCC, remains controversial. Here, we aimed to investigate the functions of PSMA7 in cSCC pathogenesis. PATIENTS AND METHODS: Clinicopathological characteristics were evaluated in 131 patients with cSCC using tissue sections. The expression of PSMA7, nucleotide-binding oligomerization domain-containing protein 1 (NOD1), and mitochondrial antiviral signaling protein (MAVS) was determined in cSCC tissue sections using immunohistochemical staining. The effect of PSMA7 expression on the biological behavior of cSCC cells was investigated in vitro. RESULTS: High immunoreactivity of PSMA7 (high-PSMA7) was detected in 53 (40.5%) patients with cSCC and was significantly associated with histologic grade (p=0.008) and favorable recurrence-free survival (p=0.018). The expression of PSMA7 and NOD1 (p=0.026) and MAVS (p=0.032) was negatively correlated in cSCC tissues. Contrary to the results of the cohort study, cell viability and invasiveness significantly decreased after PSMA7 down-regulation in cSCC cells in vitro. mRNA expression of tumor necrosis factor-alpha, interleukin-1 alpha (IL-1α), IL-6, and IL-8 were significantly increased after PSMA7 down-regulation in cSCC cells (all p=0.002). CONCLUSION: PSMA7-mediated degradation of NOD1 and MAVS as well as the subsequent reduction of the cancer-associated cytokine network may be a crucial mechanism of the antitumoral function of PSMA7 in patients with cSCC.

A nomogram combining clinical factors and biomarkers for predicting the recurrence of high-risk cutaneous squamous cell carcinoma.

BACKGROUND: Although determining the recurrence of cutaneous squamous cell carcinoma (cSCC) is important, currently suggested systems and single biomarkers have limited power for predicting recurrence. OBJECTIVE: In this study, combinations of clinical factors and biomarkers were adapted into a nomogram to construct a powerful risk prediction model. METHODS: The study included 145 cSCC patients treated with Mohs micrographic surgery. Clinical factors were reviewed, and immunohistochemistry was performed using tumor tissue samples. A nomogram was constructed by combining meaningful clinical factors and protein markers. RESULTS: Among the various factors, four clinical factors (tumor size, organ transplantation history, poor differentiation, and invasion into subcutaneous fat) and two biomarkers (Axin2 and p53) were selected and combined into a nomogram. The concordance index (C-index) of the nomogram for predicting recurrence was 0.809, which was higher than that for the American Joint Committee on Cancer (AJCC) 7th, AJCC 8th, Brigham and Women's Hospital, and Breuninger staging systems in the patient data set. CONCLUSION: A nomogram model that included both clinical factors and biomarkers was much more powerful than previous systems for predicting cSCC recurrence.

Implication of IL6-positive Cancer-associated Fibroblasts in Merkel Cell Carcinoma Pathogenesis: A Possible Modulator of Immune Microenvironment.

BACKGROUND/AIM: The role of cancer-associated fibroblasts (CAFs) in the pathogenesis of Merkel cell carcinoma (MCC) remains unknown. This study aimed to investigate the clinicopathological significance of CAF subpopulations and their association with tumor-infiltrating lymphocytes (TILs) in patients with MCC. MATERIALS AND METHODS: Clinicopathological features and the status of microenvironment fibrosis (MF) around tumor masses were evaluated in 20 MCC patient and tissue sections. Alpha-smooth muscle actin (α-SMA)-positive CAFs (α-SMA+CAFs), interleukin-6-positive CAFs (IL6+CAFs), CD4-positive TILs (CD4+TILs), and CD8-positive TILs (CD8+TILs) in MCC tissue samples were investigated using immunohistochemistry. RESULTS: In a total of 20 MCC patients, high-MF was detected in 12 (60%) patients which was significantly associated with worse progression-free survival (p=0.048), but not with overall survival. CD4+/CD8+ TILs were frequently detected in MCC tissues. High-intra-tumoral CD8+TIL was significantly associated with better overall and progression-free survival (p=0.04 and p=0.015) in our cohort. High-αSMA+ CAFs were detected in 11 (55.0%) patients and high-IL6+CAFs in 10 (50.0%) patients. A negative association was found between high-IL6+CAF and high-intra-tumoral CD8+TILs (p=0.005). Patients with high IL6+CAFs showed worse overall/progression-free survival than patients with low-IL6+CAFs (p=0.022 and p=0.035). CONCLUSION: IL6+CAFs may largely influence the tumor immune microenvironment of MCC by modulating distinct T-cell populations and functions. This study provides a possible therapeutic target to overcome resistance to immune therapies in MCC.

Risk Factors of Microscopically Tumor-Free Surgical Margins for Recurrence and Survival of Oral Squamous Cell Carcinoma Patients.

Objectives: The concept of adequate surgical margins remains controversial in oral squamous cell carcinoma (OSCC) surgery. This study aimed to identify surgical margin-related indicators that might impact recurrence and survival of OSCC patients. Materials and Methods: Histopathological examination was performed using hematoxylin-eosin-stained surgical margin tissue sections in 235 OSCC patients. Axin2 and Snail expression at the surgical margin was detected by immunohistochemistry. The impact of the Axin2-Snail cascade on tumorigenesis of the immortalized human oral keratinocyte (IHOK) line was investigated in vivo. Results: The width and dysplasia of surgical margins were not significantly associated with the outcome of OSCC patients. In a multivariate analysis using variable clinicopathologic factors and with Axin2 and Snail expression as cofactors, higher age (hazard ratio [HR]:1.050; P=0.047), Axin2 (HR:6.883; P=0.014), and Snail abundance (HR:5.663; P=0.009) had independent impacts on worsened overall survival. Similarly, lesion site in retromolar trigone (HR:4.077; P=0.010), upper (HR:4.332; P=0.005) and lower gingiva (HR:3.545; P=0.012), presence of extranodal extension (HR:9.967; P<0.001), perineural invasion (HR:3.627; P=0.024), and Snail abundance (HR:3.587; P<0.001) had independent impacts on worsened recurrence-free survival. Furthermore, Axin2 knockdown induced decreased Snail expression and attenuated tumorigenesis in the IHOK line. Conclusion: Histopathological examination of surgical margins may not be reliable to predict OSCC patient outcome. Molecular analysis may provide a more accurate risk assessment of surgical margins in OSCC. In particular, Axin2 and Snail are potential predictive biomarkers for the risk assessment of surgical margins in OSCC.