Tertiary lymphoid structures in oral lichen planus and oral epithelial dysplasia with lichenoid features: A comparative study

B Cells Infiltration Potentially Responded Better to Systemic Corticoids in Oral Lichen Planus and Oral Lichenoid Lesions

Oral lichen planus (OLP) and oral lichenoid lesion (OLL) are chronic inflammatory diseases involving the oral mucosa. B cells infiltration in OLP and OLL, however, little is known about these cells in OLP and OLL. To analyze the function and infiltrating features of B lymphocytes in OLP and OLL, and to preliminarily evaluate their correlation with clinical outcomes. Tissue samples were collected from OLP, OLL, and healthy mucosa. The phenotypes and amounts of B cells in tissues were analyzed by single-cell sequencing. Their proportion and infiltrating features in tissues were examined by immunohistochemistry and immunofluorescence. With the systemic medication of corticoids, the correlation between B cells infiltrating characteristics and the clinical outcomes were evaluated. A quantified proportion increase of B cells was shown in both OLP and OLL. B cells in OLP demonstrated heightened activation and enhanced regulation in immune response. A cohort of 100 patients with OLP/OLL and 13 healthy controls were examined to investigate the B cells infiltration pattern. B cells were distributed in the superficial layer of lamina propria in 92.9% and 41.9% of OLP and OLL, respectively(P < 0.01); focally distributed in 25.0% and 62.9% of OLP and OLL, respectively(P < 0.01). With the systemic medication of corticoids, the cases with B cell infiltration (B+) in OLP and OLL groups showed a statistically significant reduction in REU scores before and after treatment (P < 0.01). B cells are widely present in OLP and OLL, and B cell infiltration in OLP and OLL are related to the better therapeutic effect of oral corticoids.

4-nitroquinoline 1-oxide-induced oral epithelial lesions exhibit time- and stage-dependent changes in the tumor immune microenvironment

Oral tongue squamous cell carcinoma (OTSCC) is the most common cancer of the oral cavity and is associated with high morbidity due to local invasion and lymph node metastasis. Tumor infiltrating lymphocytes (TILs) are associated with good prognosis in oral cancer patients and dictate response to treatment. Ectopic sites for immune activation in tumors, known as tertiary lymphoid structures (TLS), and tumor-associated high-endothelial venules (TA-HEVs), which are specialized lymphocyte recruiting vessels, are associated with a favorable prognosis in OSCC. Why only some tumors support the development of TLS and HEVs is poorly understood. In the current study we explored the infiltration of lymphocyte subsets and the development of TLS and HEVs in oral epithelial lesions using the 4-nitroquinoline 1-oxide (4NQO)-induced mouse model of oral carcinogenesis. We found that the immune response to 4NQO-induced oral epithelial lesions was dominated by T cell subsets. The number of T cells (CD4+, FoxP3+, and CD8+), B cells (B220+) and PNAd+ HEVs increased from the earliest to the latest endpoints. All the immune markers increased with the severity of the dysplasia, while the number of HEVs and B cells further increased in SCCs. HEVs were present already in early-stage lesions, while TLS did not develop at any timepoint. This suggests that the 4NQO model is applicable to study the dynamics of the tumor immune microenvironment at early phases of oral cancer development, including the regulation of TA-HEVs in OTSCC.

The clinical and prognostic significance of CMTM6/PD-L1 in oncology

The recent discovery of CMTM6 and to a lesser extent CMTM4, two members of the chemokine-like factor (CKLF)-like MARVEL transmembrane domain-containing family, as master positive regulators of PD-L1 expression, the primary ligand of programmed cell death 1 (PD-1), on tumor and immune cells has opened new horizons for investigating the role of CMTM6/CMTM4 in different aspects of oncology including their clinical and prognostic values in different cancer types. The absence of a specific review article addressing the available results about the clinical and prognostic roles of CMTM6 alone and/or in combination with PD-L1 in cancer has encouraged us to write this paper.