Intraepithelial Macrophage Expressing CD163 Is a Histopathological Clue to Evaluate the Malignant Potency of Oral Lichenoid Condition: A Case Report and Immunohistochemical Investigation

The Immune Cells in the Development of Oral Squamous Cell Carcinoma

A still unresolved issue surrounding tumor formation concerns the role that the immune system plays in preventing the formation and progression of neoplasia, including oral squamous cell carcinoma (OSCC). Antitumor immunity has historically been seen as a critical barrier for cancer cells to develop, grow and spread, and this can be modulated using immunotherapies to achieve antitumor clinical responses. However, it has recently become clear that tumor-associated immunity, particularly the inflammatory microenvironment, has the paradoxical effect of enhancing tumorigenesis and progression. In this review, we discuss the multifaceted function of infiltrating immune cells in suppressing or promoting premalignancy and cancer. In particular, we report on the evidence supporting a role for T lymphocytes, dendritic cells, macrophages, and neutrophils in the development and progression of oral potentially malignant disorders (OPMD) and OSCC. We also draw attention to the clinical relevance of immune cell phenotypes and associated molecules for use as biomarkers and to the translatability of current research findings to improve classification systems and precision medicine in patients with OSCC.

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

OBJECTIVE

Tertiary lymphoid structures (TLSs) provide sites for antigen presentation and activation of lymphocytes, promoting their infiltration; thus, enhancing specific immune responses. The aim of this comparative cross-sectional study was to reveal the characteristics and influence of TLSs in oral lichen planus (OLP) and oral epithelial dysplasia (OED) with lichenoid features.

METHODS

Clinical information and samples of 51 OLP and 19 OED with lichenoid features were collected. Immunohistochemistry was performed, and the structures where CD20+ B cells and CD3+ T cells aggregated with peripheral lymph node addressin positive (PNAd+) vessels were defined as TLSs. The results and clinical information were analysed.

RESULT

TLS were found in 44 (86.3%) patients with OLP and 19 (100%) patients with OED. The TLS score was higher in OED group (p = 0.023), accompanied by an increased number of PNAd+ vessels. The TLS was significantly correlated with PNAd+ vessels (p = 0.027), CD20+ B (p < 0.001) and CD208+ dendritic cells (p = 0.001). Foxp3+ Treg cells but not CD8+ T cells infiltrated more severely in OED (p = 0.003) and increased when TLS score was high (p = 0.002).

CONCLUSIONS

This study revealed the widespread development of TLSs in the OLP and OED. The presence of TLSs showed a close relationship with dysplasia and may increase malignant potency by over-inducing Treg cells.

Tongue Cancer Cell-Derived CCL20 Induced by Interaction With Macrophages Promotes CD163 Expression on Macrophages

Background

CD163-positive macrophages contribute to the aggressiveness of oral squamous cell carcinoma. We showed in a previous report that CD163-positive macrophages infiltrated not only to the cancer nest but also to its surrounding epithelium, depending on the presence of stromal invasion in tongue carcinogenesis. However, the role of intraepithelial macrophages in tongue carcinogenesis remains unclear. In this study, we assessed the biological behavior of intraepithelial macrophages on their interaction with cancer cells.

Materials and Methods

We established the indirect coculture system (intraepithelial neoplasia model) and direct coculture system (invasive cancer model) of human monocytic leukemia cell line THP-1-derived CD163-positive macrophages with SCC25, a tongue squamous cell carcinoma (TSCC) cell line. Conditioned media (CM) harvested from these systems were analyzed using cytokine array and enzyme-linked immunosorbent assay and extracted a specific upregulated cytokine in CM from the direct coculture system (direct CM). The correlation of both this cytokine and its receptor with various clinicopathological factors were evaluated based on immunohistochemistry using clinical samples from 59 patients with TSCC. Moreover, the effect of this cytokine in direct CM on the phenotypic alterations of THP-1 was confirmed by real-time polymerase chain reaction, western blotting, immunofluorescence, and transwell migration assay.

Results

It was shown that CCL20 was induced in the direct CM specifically. Interestingly, CCL20 was produced primarily in SCC25. The expression level of CCR6, which is a sole receptor of CCL20, was higher than the expression level of SCC25. Our immunohistochemical investigation showed that CCL20 and CCR6 expression was associated with lymphatic vessel invasion and the number of CD163-positive macrophages. Recombinant human CCL20 induced the CD163 expression and promoted migration of THP-1. We also confirmed that a neutralizing anti-CCL20 antibody blocked the induction of CD163 expression by direct CM in THP-1. Moreover, ERK1/2 phosphorylation was associated with the CCL20-driven induction of CD163 expression in THP-1.

Conclusions

Tongue cancer cell-derived CCL20 that was induced by interaction with macrophages promotes CD163 expression on macrophages.

Alteration of Macrophage Infiltrating Compartment: A Novel View on Oral Carcinogenesis

BACKGROUND

The mortality of oral squamous cell carcinoma (OSCC) has remained high for decades; therefore, methods for early detection of OSCC are warranted. However, in the oral cavity, various mucosal diseases may be encountered, including reactive lesions and oral potentially malignant disorders, and it is difficult to differentiate OSCC from these lesions based on both clinical and histopathological findings. It is well known that chronic inflammation contributes to oral cancer development. Macrophages are among the most common inflammatory cells in cancer stromal tissue and have various roles in cancer aggressiveness. Although the roles of macrophages in cancer development have attracted attention, only a few studies have linked macrophages to carcinogenesis, particularly, oral precancerous lesions.

SUMMARY

This review article consists of 3 parts: first, we summarize current knowledge on macrophages in human various epithelial precancerous lesions, excluding the oral cavity, to show the importance and gaps in knowledge regarding macrophages in carcinogenesis; second, we review published data related to the role of macrophages in oral carcinogenesis; finally, we present a novel view on oral carcinogenesis, focusing on crosstalk between epithelial cells and macrophages. Key Messages: The biological features of macrophages in oral carcinogenesis differ drastically depending on the anatomical compartment that they infiltrate. Focusing on the alteration of macrophage infiltrating compartment may serve as a useful novel approach for studying the role of the macrophages in oral carcinogenesis and for gaining further insight into cancer prevention and early detection.