Clinicopathological analysis of 134 patients with squamous cell carcinoma of the mandibular gingiva.

Objective: The accurate assessment of the involvement of mandibular gingival squamous cell carcinoma (SCC) is essential for determining the extent of resection and is also useful for predicting lymph node metastasis and prognosis. The purpose of this study was to investigate the factors for predicting the prognosis. Study design: We reviewed 134 patients with mandibular gingival SCC treated between 2008 and 2017. The clinical findings, TN stage, relationship between radiographical type and histological pattern, and factors affecting the survival rate were investigated. Results: The moth-eaten radiographic type was significantly associated with histologically infiltrative pattern. For all 134 cases, the 5-year OS was 89.5 %, and 5-year DSS was 93.9 %. The 5-year DSS was 95.0 % for cN0 and/or pN0 cases and 90.3 % for pN (+) cases, with a significant difference. The significant risk factors for lymph node metastasis were teeth extractions by previous physicians and moth-eaten radiographic type. Conclusion: The risk factor for poor prognosis was lymph node metastasis. In addition, teeth extractions by previous physicians and moth-eaten radiographic type were the risk factors for lymph node metastasis. It is recommended that these cases be treated considering the possibility of cervical lymph node metastasis.

Invasion of the bucco-mandibular space by oral squamous cell carcinoma: histopathological analysis of invasion pattern.

Background: This study aimed to determine the patterns of invasion of oral squamous cell carcinoma (OSCC) into the bucco-mandibular space (BMS) using detailed histopathological analysis and to assess clinical outcomes. Methods: Patients with OSCC who underwent segmental mandibulectomy or hemi-mandibulectomy combined with resection of the BMS between 2012 and 2021 were included. The invasions of the BMS were classified into three patterns. Pattern A was defined as a horizontal invasion, Pattern B as a vertical invasion, and Pattern C as an expansive invasion. Results: In total, 109 patients were reviewed. Of these 109 patients, the primary tumor affected the lower gingiva in 78 patients, the buccal mucosa in 18 patients, and was a primary intraosseous carcinoma of the mandible in 13 patients. Invasion of the BMS was significantly associated with a higher pathological T stage, positive/close margins, and lower disease-free survival (DFS) rates. The DFS rates were 86.7% and 66.0% in the BMS non-invasion and invasion groups, respectively. The DFS rates for each type of invasion were 82.1% for Pattern A, 67.4% for Pattern B, and 48.0% for Pattern C (P=0.277). Conclusion: Patients with BMS invasion have a poorer prognosis than those without invasion of the BMS. Therefore, adjuvant therapy is necessary, especially in Patterns B and C. Evaluation of preoperative BMS invasion patterns is important for predicting the prognosis of OSCC.

Personal immune profiles: Diversity and prognostic value for oral tongue squamous cell carcinoma evaluated by comprehensive immune parameter analyses with multiplex immunofluorescence.

OBJECTIVES: Understanding the tumor immune microenvironment is becoming increasingly necessary for risk prediction and treatment selection. In particular, oral cancer has various immunosuppressive characteristics in the tumor microenvironment. Therefore, we comprehensively assessed the immune profiles of oral tongue squamous cell carcinoma (OTSCC). MATERIALS AND METHODS: Multiplex immunofluorescence and tissue imaging analyses were performed to evaluate immune profiles at the invasive tumor front of 60 OTSCC surgical specimens. We analyzed 58 immune parameters including the density and proportion (%) of total leukocytes (Leu) and T cells, six subsets of T and myeloid cells, and the expression of programmed cell death-1 (PD-1) and PD-1 ligand 1 (PD-L1). RESULTS: The density, proportion, and location of CD45+ Leu, three T cell subsets (CD8+, Foxp3-CD4+ conventional, and Foxp3+CD4+ regulatory T cells), CD163-CD68+ M1 and CD163+CD68+ M2 macrophages, and neutrophils were highly variable at the individual level. The density and proportion of M2 macrophages were significantly lower in the T1 stage group. Risk prediction analyses for recurrence and/or metastasis (R/M) showed that R/M (+) T1 cases had significantly higher M2 density and percentages. CONCLUSIONS: The immune profiles of OTSCC patients are diverse and cannot be predicted from clinicopathological information alone. The M2 macrophage abundance is a potential candidate biomarker for R/M in the early stage of OTSCC. Personal immune profiling may provide beneficial information for risk prediction and treatment selection.

Buccinator muscle invasion is a risk factor for cervical lymph node metastasis in squamous cell carcinoma of the buccal mucosa: A retrospective study.

The present study aimed to determine the risk factors associated with cervical lymph node metastasis (CLNM) in patients with buccal mucosa squamous cell carcinoma (BMSCC). This retrospective study included patients with primary BMSCC who underwent surgery at the Department of Oral and Maxillofacial Surgical Oncology of Tokyo Medical and Dental University (Tokyo, Japan) between January 2008 and December 2017. The following data were collected and analyzed: Sex, age, primary lesion subsite, tumor/node/metastasis stage, clinical growth patterns, tumor differentiation, lymphovascular and perineural invasion, mode of invasion, pathological depth of invasion, extent of tumor invasion, and clinical outcome of patients with BMSCC. Multivariate analysis was performed to identify the possible risk factors for CLNM. A total of 75 patients were included in the present study, among whom 30 (40%) were found to have histological CLNM. Of the 33 patients with buccinator muscle infiltration by the tumor, 24 (72.7%) had CLNM. Multiple logistic regression analysis revealed that buccinator muscle invasion was the most significant predictive risk factor for CLNM in BMSCC. The present study found that tumor invasion of the buccinator muscle was the most significant predictive risk factor for CLNM in BMSCC. Therefore, elective neck dissection should be performed if buccinator muscle invasion is identified in patients with BMSCC.

Massive low-grade myxoid liposarcoma of the floor of the mouth: A case report and review of literature.

BACKGROUND: Oral liposarcoma is an extremely rare lesion that is often clinically misdiagnosed as a benign tumor due to its asymptomatic and indolent clinical course. Here, we report a case of massive low-grade myxoid liposarcoma (MLS) of the floor of the mouth. CASE SUMMARY: A 71-year-old man presented with a huge mass in the left floor of the mouth. A biopsy was performed, and a diagnosis of a myxoid tumor suspicious for low-grade MLS or myxoma was made. Gadolinium-enhanced T1-weighted magnetic resonance imaging showed an intensely enhanced tumor lesion that occupies the left sublingual space and extends to the submandibular space. Submandibular dissection, tumor resection, and reconstruction with a radial forearm flap were performed. The surgical specimen exhibited histologically low-grade MLS. Fused in sarcoma (FUS, also known as TLS) and DNA damage-inducible transcript 3 (DDIT3, also known as CHOP) break-apart was not detected in the fluorescence in situ hybridization analysis. The tumor was completely encapsulated and did not require additional treatment. Furthermore, no recurrence was reported 40 mo after surgery. CONCLUSION: We experienced an extremely rare, massive, low-grade MLS emerging from the floor of the mouth. Oftentimes, an MLS of the floor of the mouth lacks significant clinical findings and is often misdiagnosed. Although no FUS-DDIT3 fusion gene was detected, a low-grade MLS was ultimately diagnosed based on the histological findings.

VSIG4/CRIg directly regulates early CD8+ T cell activation through its counter-receptor in a narrow window.

T-cell responses are fine-tuned by positive and negative co-signal molecules expressed on immune cells and adjacent tissues. VSIG4 is a newly identified member of the B7 family of ligands, which negatively regulates innate inflammatory and CD4+ T cell-mediated responses. However, little is known about the direct effects of VSIG4, which are exerted through an unidentified counter-receptor on CD8+ T cells. We investigated the binding of the VSIG4-Ig fusion protein during CD8+ T cell activation, and the functional involvement of VSIG4 pathway, using VSIG4-Ig and VSIG4-transfectants. VSIG4-Ig binding to CD8+ T cells was temporally observed in the CD44high phenotype during initial activation. VSIG4-Ig binding was observed earlier than the induction of PD-1, LAG3, and TIM-3, which are immune checkpoint receptors for exhausted CD8+ T cells. Immobilized VSIG4-Ig inhibited anti-CD3/CD28 mAb-induced CD8+ T cell activation, as indicated by proliferation and IFN-γ production, similar to the downregulation of T-bet and Eomesodermin transcription factors. VSIG4 on FcγR+ P815 or specific antigen-presenting E.G7 cells inhibited the generation of effector CD8+ T cells, as indicated by proliferation, IFN-γ and TNF-α expression, and granule degradation, compared to parental cells. However, the window for the regulatory function of VSIG4 was narrow and dependent on the strength of TCR (and CD28)-mediated signals. Our results suggested that VSIG4 directly delivers co-inhibitory signals via an as-yet unidentified counter-receptor on activated CD8+ T cells. VSIG4-mediated CD8+ T cell tolerance might contribute to the steady-state maintenance of homeostasis.

MYC-PDL1 axis reduces sensitivity to nivolumab in recurrent head and neck squamous cell carcinoma.

Patients with recurrent or metastatic squamous cell carcinoma of the head and neck (R/M HNSCC) have a poor prognosis. Recently, the use of immune checkpoint inhibitors (ICIs) for drug treatment has been expanding . However, the response rate to immunotherapy is low. Therefore, the identification of predictive biomarkers of response and resistance to ICIs is required for various types of malignant tumors. We report the case of a patient with recurrent and metastatic HNSCC who simultaneously showed different responses to nivolumab in metastatic lesions. After administering nivolumab, metastasis to the multiple cervical lymph node metastases showed a significant reduction, whereas a new metastasis to the right axillary lymph node occurred . Each surgical specimen was analyzed using the cancer gene panel test (FoundationOne CDx) to elucidate why treatment response is distinct among the same patient. Next-generation sequencing revealed MYC amplification and programmed cell death-1 loss in the right axillary lymph nodes but not cervical lymph nodes. Furthermore, t he histopathological findings suggested that MYC amplification regulated programmed death-ligand 1 expression and was involved in a decreased response to ICIs. This result is expected to help predict the efficacy of ICI treatment and select therapeutic agents.

Discrepancy Between Clinical Diagnosis and Whole-exome Sequencing-based Clonality Analysis of Synchronous Multiple Oral Cancers.

BACKGROUND/AIM: The definition of multiple oral cancers is based on the distances between the tumors. However, it is not possible to accurately predict tumor origins based only on clinical criteria. PATIENTS AND METHODS: We performed whole-exome sequencing (WES) to analyze the genetic alterations in five tumors of two patients who underwent surgery in our hospital. RESULTS: In case 1, the distances between tumors on the right mandibular gingiva and buccal mucosa were more than 15 mm, leading to a clinical diagnosis of multiple primary tumors. WES revealed common mutations between tumors, suggesting that the tumors were derived from the same clone. In contrast, in case 2, the distance between tumors on the right side of the tongue was only 10 mm, but the tumors were diagnosed as double primary tumors because their mutations were completely different. CONCLUSION: WES, rather than the available clinical criteria, can clarify the clonal origins of multiple oral cancers.

Renal cell carcinoma metastasis to the maxillary bone successfully treated with surgery after vascular embolization: a case report.

BACKGROUND: Metastasis of renal cell carcinoma to the oral cavity is rare. Renal cell carcinoma metastases are regarded as radioresistant tumors and surgery is recommended. However, since metastatic renal cell carcinoma has poor prognosis and is composed of abundant blood vessels, it is sometimes difficult for clinicians to choose surgical therapy. Here, we report a case of a patient with renal cell carcinoma metastasis to the maxillary bone, which was successfully controlled by surgical therapy after vascular embolization, and provide a detailed literature review regarding the treatments and outcomes of renal cell carcinoma metastasis to the oral cavity. CASE PRESENTATION: An 89-year-old Japanese man presented with an 8 × 8-mm granulomatous tumor with palpable pulsation in the left upper gingiva, which had been clinically suspected as an arteriovenous malformation or neoplastic lesion with rich blood vessels. Our patient had undergone left nephrectomy for clear cell carcinoma 7 years prior. Pulmonary metastasis had appeared 3 years later. After intravascular embolization, our patient underwent tumor resection of the maxilla with little intraoperative blood loss. The tumor was diagnosed on histopathology as a metastasis of clear cell renal cell carcinoma to the maxillary bone. Seventeen months after surgery, he died because of pulmonary metastasis without evidence of recurrence in the oral cavity. CONCLUSIONS: Our literature review reveals that oral metastatic lesions of renal cancer often exhibit rapid enlargement and cause severe symptoms, such as dysphagia and bleeding. Although oral metastasis of renal cell carcinoma has a poor prognosis due to the presence of concurrent disseminated metastases, surgical therapy may be recommended because of its high local control rate and ability to maintain quality of life. Preoperative vascular embolization is considered to be effective to reduce intraoperative hemorrhage, which leads to safe surgery.

Orthotopic tongue squamous cell carcinoma (SCC) model exhibiting a different tumor-infiltrating T-cell status with margin-restricted CD8+ T cells and regulatory T cell-dominance, compared to skin SCC.

The immunological, and especially T cell, status of the tumor microenvironment affects tumor development and the efficacy of cancer treatment. To devise suitable combination therapies based on the results of murine tumor models, a more realistic orthotopic model is required. In this study, we generated a murine model of tongue squamous cell carcinoma (SCC), in which the tumor-immune cell interactions were recapitulated, and examined tumor- and T-cell status compared to a skin-transplanted SCC model by multiplex immunofluorescence staining for epidermal growth factor receptor, CD31, CD8, CD4, and Foxp3. Administration of SCCVII cells did not induce undesirable tissue damage or inflammation. In tongue SCC, abundant T-cell infiltration was observed at the tumor margin, but not in the core. Tongue SCC predominantly showed CD8+ T or Foxp3+ regulatory T cell (Treg)-infiltration. In contrast, skin-transplanted SCC showed abundant infiltration of T cells in the whole tumor area, which was dominated by Tregs. An orthotopic tongue SCC model showed differences in tumor and T-cell status compared to the skin-transplanted SCC model. Our tongue SCC model may enhance understanding of tumor-host interactions and enable evaluation of therapeutic efficacy.

Endogenous IL-33 exerts CD8+ T cell antitumor responses overcoming pro-tumor effects by regulatory T cells in a colon carcinoma model.

Interleukin-33 (IL-33) is a nuclear-associated cytokine of the IL-1 family. IL-33 and its receptor ST2 axis exert conflicting anti-tumor and pro-tumor effects in various tumors. In this study, we examined the role of endogenously produced IL-33 in the colon-26 tumor model, in which involvement of the IL-33:ST2 pathway was negligible on the tumor side. We found that the generation of regulatory T cells (Tregs) and CD8+ T cells, and IFN-γ expression by both CD4+ and CD8+ T cells (T cell activation) were impaired in IL-33-deficient mice. Overall antitumor responses, assessed by tumor growth and IFN-γ expression by tumor-infiltrating CD8+ T cells, were also impaired, even after Treg adjustment prior to tumor inoculation. These results indicate that endogenous IL-33 augmented CD8+ T cell-mediated antitumor responses in this colon carcinoma model, with higher CD8+ T cell-infiltration and overcoming pro-tumor effects by increased Tregs. Exogenous application of IL-33 into the tumors did not enhance CD8+ T cell-mediated antitumor responses despite marked elevation of innate responses showing upregulation of proinflammatory cytokine/chemokine expression, neutrophil recruitment, and dendritic cell activation. Our results suggest a dual role for endogenous IL-33 in antitumor responses and suggest that the balance of CD8+ T cells:Tregs in the tumor microenvironment is one of key factors for estimating the contribution of IL-33-mediated antitumor responses. Therefore, the development of IL-33-based cancer immunotherapy may require a target cell-specific approach.

Differences of tumor-recruiting myeloid cells in murine squamous cell carcinoma influence the efficacy of immunotherapy combined with a TLR7 agonist and PD-L1 blockade.

OBJECTIVES: The immune status of the tumor microenvironment has a marked impact on clinical outcomes. Here we examined the immune environments of tumor-infiltrating leukocytes (TILes) in two murine models of squamous cell carcinoma and compared the effects of immunotherapeutic agents, including a TLR7 agonist and an immune checkpoint inhibitor, and a chemotherapeutic agent, gemcitabine, in these models. MATERIALS AND METHODS: TILes from NR-S1- and SCCVII-grafted mice were analyzed by flow cytometry. NR-S1-inoculated mice received resiquimod (a synthetic TLR7 agonist), an anti-PD-L1 antibody, or both, and tumor growth and TILs were examined. Gemcitabine was administered to deplete CD11b+ cells. RESULTS: More than 50% of TILes from NR-S1- and SCCVII-inoculated mice were CD11b+Gr-1+ cells. A major fraction of NR-S1 CD11b+ cells was Ly6GhighLy6Clow-negaF4/80- tumor-associated neutrophils (TANs) and the majority of SCCVII CD11b+ cells were Ly6GlowLy6C-F4/80+ tumor-associated macrophages. NR-S1 TANs did not express MHC class II and CD86, but did express reactive oxygen species and PD-L1. Resiquimod, alone and in combination with an anti-PD-L1 antibody, did not regress NR-S1 tumors, but the combination increased the CD8/regulatory T cell-ratio, and IFN-γ and PD-1 expression in CD8+ TILes. Pre-administration of low-dose gemcitabine prior to the combination treatment suppressed the progression of NR-S1 tumors. CONCLUSIONS: NR-S1 tumors with abundant recruitment of TANs were resistant to treatments with a TLR7 agonist, alone and in combination with PD-1 blockade, and required an additional gemcitabine treatment. The phenotype and status of tumor-infiltrating CD11b+ myeloid cells may influence the efficacy of immunotherapeutic agents.

Systemic administration of a TLR7 agonist attenuates regulatory T cells by dendritic cell modification and overcomes resistance to PD-L1 blockade therapy.

Research on immune checkpoint blockade therapy has made great progress in cancer immunotherapy, but the number of patients who benefit from this therapy remains limited. In this study, we examined the effects of monotherapy with systemic low-dose resiquimod, a synthesized TLR7 agonist, and examined its combined effects with PD-L1 blockade in two PD-L1 blockade-resistant tumor models (SCCVII and Colon 26). Resiquimod monotherapy in SCCVII tumors, representing impaired CD8+ T cell function and accelerated regulatory T cells (Tregs) within the tumors, efficiently reduced tumor growth with more recruitment of CD8+ T cells and a reduction of Treg. The results of resiquimod monotherapy in Colon 26, representing impaired Treg recruitment, were inferior to that in SCCVII. Combined resiquimod treatment with PD-L1 blockade exerted clear additional effects, as it was associated with reduced tumor size, attenuation of Tregs, and an increased ratio of CD8+ T cells/Tregs in both tumors. Systemic administration of low-dose resiquimod induced a transient and rapid activation of plasmacytoid and conventional dendritic cells, resulting in enhanced priming of T cells in regional lymph nodes. Experiments with more limited doses of resiquimod that did not yield beneficial effects after single treatment, showed additional effects to PD-L1 blockade and comparable antitumor effects when the frequency of anti-PD-L1 therapy was decreased. Our results suggest that systemic administration of low-dose resiquimod is useful as a companion drug to PD-1/PD-L1 blockade therapy.

Differential contribution of three immune checkpoint (VISTA, CTLA-4, PD-1) pathways to antitumor responses against squamous cell carcinoma.

V domain-containing Ig suppressor of T-cell activation (VISTA)/PD-1H is a novel immune checkpoint molecule for regulating T-cell activation. We examined the effects of anti-VISTA mAb monotherapy and combination therapy with CTLA-4 or PD-1 blockade in a squamous cell carcinoma (SCCVII) model. VISTA monotherapy did not show clear tumor growth regression, but efficiently induced CD8(+) T cell activation by converting resting and exhausted cells into functional effector cells. VISTA monotherapy did not inhibit recruitment of regulatory T cells (Tregs) in the tumor microenvironment (TME). As an additional treatment to VISTA, CTLA-4 blockade, but not PD-1 blockade, elicited further tumor regression. The CTLA-4 and VISTA combination efficiently inhibited Treg recruitment and increased the ratios of both CD8 T/Treg and CD4 conventional T (Tcon)/Treg in the TME, whereas the PD-1 and VISTA combination dramatically increased tumor-recruiting CD8(+) T cells, but markedly reduced the Tcon/Treg ratio. Our results demonstrate that VISTA blockade efficiently converts CD8(+) T cells into functional effector T cells, but is not sufficient to regress tumor growth due to weak Treg suppression in the TME. Our results suggest that combined CTLA-4 and VISTA blockade is more efficacious than combined PD-1 and VISTA blockade for tumors like head and neck squamous cell carcinoma in which Treg-mediated immune regulation is dominant.