Dynamic alterations of circulating T lymphocytes and the clinical response in patients with head and neck squamous cell carcinoma treated with nivolumab.

Cancer immunotherapy using immune checkpoint inhibitors (ICIs) has been recognized as a novel therapeutic option for head and neck squamous cell carcinoma (HNSCC). However, only approximately 20-30% of patients with recurrent/metastatic (R/M) HNSCC benefit. Moreover, the mechanisms underlying the response to ICIs remain unclear. We investigated the proportion, activation status, and expression level of immune checkpoint molecules in circulating T cell subsets in R/M HNSCC patients treated with nivolumab using flow cytometry and mass cytometry, and then determined whether treatment response was associated with these values. We also assessed the changes in the frequency of tumor-associated antigens, MAGE-A4 and p53, -specific T cells prior to and after nivolumab treatment using the IFN-γ ELISPOT assay. The proportion of activated CD4+ and CD8+ TEMRA cells significantly increased in the disease-controlled patients but not in disease-progressed patients. As expected, the expression of PD-1 in T cells markedly decreased regardless of the therapeutic response. Meanwhile, T cell immunoglobulin mucin-3 expression on CD8+ T cells was significantly higher in patients with disease progression than in disease-controlled patients after treatment. The frequency of the tumor-associated antigens, MAGE-A4- and p53-specific T cells, was not correlated with clinical responses; however, in the disease-controlled patients, the frequency of MAGE-A4-specific T cells was significantly augmented. We concluded that in R/M HNSCC patients treated with nivolumab, circulating T cells show dynamic alterations depending on treatment efficacy. An analysis of the immunokinetics of circulating T cells could thus provide new insights into rational therapeutic strategies in cancer immunotherapy for HNSCC.

Systemic immune responses are associated with molecular characteristics of circulating tumor cells in head and neck squamous cell carcinoma.

Systemic immunity mediated by circulating immune cells may affect clinical features, as well as the characteristics of circulating tumor cells (CTCs) in patients with head and neck squamous cell carcinoma (HNSCC). The present study aimed to analyze the influence of circulating immune cells, using their markers, on clinical features to investigate the association between systemic immunity and the molecular characteristics of CTCs. Circulating immune-cell markers were associated with disease progression and clinical outcomes in patients with HNSCC. Meanwhile, there was no significant association between the presence of CTCs and systemic immune-related markers. Moreover, phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit a expression in CTCs was significantly associated with higher lymphocyte counts (P=0.035) and an increased prognostic nutrition index (P=0.0157). Patients with CTCs expressing CD47 exhibited significantly higher neutrophil (P=0.0031) and monocyte (P=0.0016) counts. Patients with CTCs expressing programmed cell death 1 ligand 2 exhibited lower C-reactive protein (CRP) levels (P=0.0271) and a decreased CRP/albumin ratio (P=0.0207). The current results suggested that the interaction between CTCs and circulating immune cells may provide survival advantages via molecular alterations to CTCs.

Molecular phenotypes of circulating tumor cells and efficacy of nivolumab treatment in patients with head and neck squamous cell carcinoma.

The emergence of immune checkpoint inhibitors (ICIs) has revolutionized the treatment of recurrent/metastatic (R/M) head and neck squamous cell carcinoma (HNSCC). Biomarkers of the therapeutic efficacy of ICIs have been extensively investigated. In this study, we aimed to analyze whether molecular phenotypes of circulating tumor cells (CTCs) are associated with treatment responses and clinical outcomes in patients with R/M HNSCC treated with nivolumab. Peripheral blood samples were collected before treatment initiation and after four infusions of nivolumab. CTCs isolated by depletion of CD45-positive cells were analyzed to determine the expression of EPCAM, MET, KRT19, and EGFR using real-time quantitative polymerase chain reaction. CTC-positive samples were analyzed to determine the expression of PIK3CA, CCND1, SNAI1, VIM, ZEB2, CD44, NANOG, ALDH1A1, CD47, CD274, and PDCD1LG2. Of 30 patients treated with nivolumab, 28 (93.3%) were positive for CTCs. In 20 CTC-positive patients, molecular alterations in CTCs before and after nivolumab treatment were investigated. Patients with MET-positive CTCs had significantly shorter overall survival than those with MET-negative CTCs (p = 0.027). The expression level of CCND1 in CTCs of disease-controlled patients was significantly higher than that of disease-progressed patients (p = 0.034). In disease-controlled patients, the expression level of CCND1 in CTCs significantly decreased after nivolumab treatment (p = 0.043). The NANOG expression in CTCs was significantly increased in disease-controlled patients after nivolumab treatment (p = 0.036). Our findings suggest that the molecular profiling of CTCs is a promising tool to predict the treatment efficacy of nivolumab.

Epithelial-Mesenchymal Transition Status of Circulating Tumor Cells Is Associated With Tumor Relapse in Head and Neck Squamous Cell Carcinoma.

BACKGROUND/AIM: We aimed to elucidate the clinical implication of the epithelial-mesenchymal plasticity of circulating tumor cells (CTCs) in patients with head and neck squamous cell carcinoma (HNSCC). PATIENTS AND METHODS: CTCs isolated from 44 patients with non-recurrent/metastatic HNSCC and 42 with recurrent/metastatic (R/M) HNSCC were classified into four epithelial-mesenchymal transition (EMT) statuses based on the expression of epithelial (keratin 19) and mesenchymal (vimentin) markers and the relationships between EMT status in CTCs and clinical factors were investigated. RESULTS: E+M- CTC phenotype was more frequent in patients without recurrence/metastasis (p=0.0468) and was also more frequent in those with a complete response (p=0.0346). The E+M+ phenotype constituted the major proportion of the CTCs detected in patients with R/M HNSCC (p=0.0374). CONCLUSION: CTCs may play unique roles at various stages of metastasis through transitioning from epithelial to mesenchymal phenotypes.