Characterization of immune cell infiltrate in tumor stroma and epithelial compartments in oral squamous cell carcinomas of Sudanese patients

Abstract

Background: Tumor immune infiltrate has been explored in oral squamous cell carcinoma (OSCC), but studies on simultaneous characterization of multiple immune cell subtypes separately in stromal and intraepithelial tumor compartments are limited.Objectives: We aimed to investigate the immune cell infiltrate in OSCC by using immunohistochemistry (IHC) for a panel of inflammatory cells in stromal and epithelial tumor compartments for a better characterization of the tumors. Methods: Thirty-six OSCC lesions and nine normal oral mucosa (NOM) samples from patients attending Khartoum Dental Teaching Hospital, Sudan were investigated for presence of tumor infiltrating lymphocytes, tumor-associated macrophages, tumorassociated neutrophils, and PD-L1 positive cells in the inflammatory infiltrate by single and double IHC. Digital quantitative analysis (Aperio Technologies Inc.) was performed separately for stromal and epithelial compartments.Results: OSCC cases displayed a higher inflammatory infiltrate in the associated stroma, but not in the epithelial compartment when compared to NOM. The immunosuppressive type of inflammatory infiltrate, that is, T regulatory cells (FoxP3 + cells) was identified to be significantly higher in the epithelial compartment of tumors with Elisabeth Sivy Nginamau and Daniela Elena Costea contributed equally to this work.

Epithelial PD‐L1 expression at tumor front predicts overall survival in a cohort of oral squamous cell carcinomas from Sudan

“…Single‐ and double‐staining IHC were performed as previously described (Gaafar et al, 2022 ). Deparaffinization and rehydration of tissue sections were performed by using xylene and graded alcohol concentrations (100%, 96%, and 70%), respectively.…”

“…Twenty-two OSCC patients recruited during 2014-2015 at the Khartoum Dental Teaching Hospital, Sudan, were included in this study. The participants were also part of the prospective cohort in which TIME in the TC was previously studied (Gaafar et al, 2022). individuals by four dentists who were trained and calibrated before data collection.…”

“…individuals by four dentists who were trained and calibrated before data collection. Tumor node metastasis staging and tobacco consumption were recorded as previously described (Gaafar et al, 2022). OS was defined as the time (in months) from the date of diagnosis till the end date of the study.…”

“…Manual annotations separately for stromal and epithelial compartments were performed at the ITF (from 5 to 7 regions with inflammatory infiltrate hotspots, with a total analyzed area of a minimum of 0.2 mm 2 ) using quantifying algorithms previously established in our laboratory (Gaafar et al, 2022).…”

“…We previously showed that despite the high abundance of inflammatory cells in tumor-associated stroma of the TC, a low intraepithelial infiltration with immune cells was observed at the TC of the majority of investigated OSCC lesions (Gaafar et al, 2022). When an immunoscore was created based on the combination of individual CD4 and FoxP3 intraepithelial TC scores, this score was found to be correlated to tumor progression (Gaafar et al, 2022).…”