Samples Of Normal Salivary Gland Tissue Research Articles

Molecular characterization of the salivary adenoid cystic carcinoma immune landscape by anatomic subsites

Adenoid cystic carcinoma (AdCC) is a slow-growing salivary gland malignancy that relapses frequently. AdCCs of the submandibular gland exhibit unique differences in prognosis and treatment response to adjuvant radiotherapy compared to other sites, yet the role of tumor anatomic subsite on gene expression and tumor immune microenvironment (TIME) composition remains unclear. We used 87 samples, including 48 samples (27 AdCC and 21 normal salivary gland tissue samples) from 4 publicly available AdCC RNA sequencing datasets, a validation set of 33 minor gland AdCCs, and 39 samples from an in-house cohort (30 AdCC and 9 normal salivary gland samples). RNA sequencing data were used for single sample gene set enrichment analysis and TIME deconvolution. Quantitative PCR and multiplex immunofluorescence were performed on the in-house cohort. Wilcoxon rank-sum, nonparametric equality-of-medians tests and linear regression models were used to evaluate tumor subsite differences. AdCCs of different anatomic subsites including parotid, submandibular, sublingual, and minor salivary glands differed with respect to expression of several key tumorigenic pathways. Among the three major salivary glands, the reactive oxygen species (ROS)/nuclear factor erythroid 2-related factor 2 (NRF2) pathway signature was significantly underexpressed in AdCC of submandibular compared to parotid and sublingual glands while this association was not observed among normal glands. Additionally, the NRF2 pathway, whose expression was associated with favorable overall survival, was overexpressed in AdCCs of parotid gland compared to minor and submandibular glands. The TIME deconvolution identified differences in CD4+ T cell populations between AdCC of major and minor glands and natural killer (NK) cells among AdCC of minor, submandibular, and parotid glands while plasma cells were enriched in normal submandibular glands compared to other normal gland controls. Our data reveal key molecular differences in AdCC of different anatomic subsites. The ROS and NRF2 pathways are underexpressed in submandibular and minor AdCCs compared to parotid gland AdCCs, and NRF2 pathway expression is associated with favorable overall survival. The CD4+ T, NK, and plasma cell populations also vary by tumor subsites, suggesting that the observed submandibular AdCC tumor-intrinsic pathway differences may be responsible for influencing the TIME composition and survival differences.

Immunohistochemical Expression of Estrogen Receptors in Pleomorphic Adenoma and Normal Salivary Gland Tissue

Background: The expression of estrogen receptors (ERs) in salivary gland tissue has been observed in some studies. Considering the histological similarity of salivary glands and breast tissue, as well as the prominent role of this receptor in the pathogenesis, treatment, and prognosis of breast tumors, this study aimed to compare the immunohistochemical expression of ERs in pleomorphic adenoma (PA) and normal salivary gland tissue and assess its possible role in salivary gland tumors. Methods: In this descriptive-analytical study, 26 samples of PA (16 females, and 10 males) and 12 samples of normal salivary gland tissue were selected. Immunohistochemical staining was performed by the standard EnVision method for ERs. The results were evaluated semi-quantitively as the percentage of the nuclear and cytoplasmic staining were analyzed independently by Mann-Whitney, Kruskal-Wallis, and Fisher’s exact tests. Results: All PA samples showed negative nuclear staining for ERs. ER expression was observed in the cytoplasm of the ducts in 27% of tumors and 59% of normal salivary gland tissue samples, but the difference was not statistically significant. In addition, no association was found between ER expression and independent variables, such as age, sex, the type of stroma, or the degree of cellularity in PA, and the location of the specimen. Conclusion: It seems that the expression of ERs does not play an effective role in the development and progression of PA. However, its occurrence in the normal salivary gland ducts is considerable, and further studies in this field seem to be necessary.

Abstract PO-092: Molecular characterization of the salivary adenoid cystic carcinoma tumor immune landscape by anatomic subsite

Abstract Introduction: Adenoid cystic carcinoma (AdCC) is typically indolent, however tends to behave more aggressively and present with perineural invasion and distant metastasis. Despite an improved understanding of AdCC pathobiology, the impact of anatomic tumor subsite (e.g., major versus minor salivary glands) on survival and response to treatment is relatively understudied. We recently discovered that submandibular AdCC’s exhibit unique differences in prognosis and treatment response to adjuvant radiotherapy. However, the impact of anatomic subsites on gene expression and immune cell composition, has not been investigated. Materials and methods: We used 4 publicly available AdCC molecular datasets (n = 37 AdCCs of different origin: 27 primary and 10 metastatic; 7 parotid (PG), 5 submandibular (SMG), 4 sublingual (SLG), 21 minor salivary gland (mG) and 21 normal salivary gland tissue samples). Data were harmonized between datasets using identical quantification procedures, followed by filtering and normalization performed simultaneously on the pooled data from all cohorts. Gene set enrichment analysis (GSEA) was performed Human Molecular Signatures Database (MSigDB) Hallmark and Oncologic signatures. Tumor immune microenvironment (TIME) decomposition was performed using a non-negative matrix factorization-based approach. GSEA and TIME differences between AdCC subsites were evaluated using Wilcoxon rank-sum and nonparametric equality-of-medians tests. Results: We identified different levels of enrichment for several key tumorigenic pathways between AdCCs arising within different anatomic subsites. Among AdCCs, major glands overexpressed the HALLMARK_SPERMATOGENESIS signature (parotid and sublingual glands), while the HALLMARK_REACTIVE_OXYGEN_SPECIES_PATHWAY (ROS) signature was significantly underexpressed in SMG AdCCs. In addition, the HALLMARK_EPITHELIAL_MESENCHYMAL_TRANSITION (EMT) signature was significantly underexpressed in both SMG and PG AdCCs. These pathway signatures were not seen in control tissue comparison samples, indicating that these features are AdCC-specific. Additionally, TIME decomposition identified differences in CD4-T cell populations (minor > major gland AdCC) and natural killer (NK) cells (increased in PG and SLG). Meanwhile, normal control comparisons revealed a significant increase in plasma cells only within SM glands. Conclusions: AdCC subsites exhibit survival and treatment-response differences, and in this study demonstrate that these anatomical sites are associated with distinct molecular features. Specifically, these different anatomical sites vary in the expression of spermatogenesis, ROS, and EMT signature-related genes. Also, CD4-T and NK cell populations vary by anatomical site, suggesting that the SMG AdCC tumor-intrinsic pathway differences observed may be responsible for influencing the TIME composition and increased prognosis associated with these tumors following adjuvant radiotherapy. Validation with additional cohorts of primary AdCCs with accurate clinical annotation are required. Citation Format: Jason Tasoulas, Travis Schrank, Steven Johnson, Kimon Divaris, Stamatios Theocharis, Trevor Hackman, Siddharth Sheth, Kedar Kirtane, Juan Hernandez-Prera, Christine Chung, Wendell Gray Yarbrough, Natalia Issaeva, Antonio Amelio. Molecular characterization of the salivary adenoid cystic carcinoma tumor immune landscape by anatomic subsite [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Innovating through Basic, Clinical, and Translational Research; 2023 Jul 7-8; Montreal, QC, Canada. Philadelphia (PA): AACR; Clin Cancer Res 2023;29(18_Suppl):Abstract nr PO-092.

Human Tissue Kallikreins in Polymorphous Adenocarcinoma: A Polymerase Chain Reaction and Immunohistochemical Study.

Polymorphous adenocarcinoma (PAC) is the second most common malignant salivary gland tumour of minor salivary glands. Human tissue kallikreins (KLKs) are a family of highly conserved serine proteases expressed by various tissues and organs. The literature demonstrates a link between KLKs and salivary gland neoplasms. The purpose of this study was to determine levels of KLK mRNA in tissue samples of PAC and to determine if KLK expression is limited to tumour cells. Nineteen cases of PAC were reviewed (1987-2013). The diagnosis was confirmed, demographic data was collected, and formalin fixed paraffin-embedded PAC and normal salivary gland tissue samples were obtained. RNA isolation was achieved, followed by conversion to complementary DNA via reverse transcription. Using PCR, the quantitative level of expression of KLKs1-15 was recorded. Samples exhibiting high and low KLK expression were selected for immunohistochemistry staining. Results revealed a statistically significant increase in mean KLK mRNA expression for KLK1, KLK4, KLK10, KLK12 and KLK15 in PAC tissue samples, compared with normal salivary gland tissue (Mann-Whitney U test, p < 0.05). Immunohistochemistry results demonstrated that KLKs were present in tumor cells. Notably, all samples demonstrating relatively higher KLK mRNA expression showed equivalent or increased staining scores relative to the low KLK mRNA expression samples. In conclusion, there appears to be aberrant kallikrein expression in polymorphous adenocarcinoma, suggesting the possibility of a kallikrein cascade influence on tumor development and progression.

Documentation of postmortem changes in salivary gland architecture and staining characteristics.

Context:Estimation of time passed since death continues to be a major problem for the forensic pathologist and its determination plays an important and vital role in medico-legal cases. The histological studies on various tissues after death have been mostly confined to single organ or tissue by individual workers at different atmospheric conditions.Aims:The aim of this study is to determine the best rehydrating solution for dehydrated tissues in postmortem examination.Settings and Design:This study was specific to salivary gland tissues and certain pattern of changes were determined during postmortem time intervals using hematoxylin and eosin stain and special stains like mucicarmine and alcian blue.Materials and Methods:The study was divided into two groups. (1) Group A: Normal tissue samples (twenty normal salivary gland tissue samples left without fixation for varying periods of time). (2) Group B: Control group (twenty normal salivary gland tissue samples immediately fixed in formalin). The three different rehydrating agents used in this study were glycerol, normal saline and modified Ruffer solution.Statistical Analysis Used:Not required.Results:Modified Ruffer solution is the best when compared to glycerol and normal saline for rehydration of dehydrated tissues.Conclusions:Thus in our study we conclude that the tissue which had been dehydrated at the crime scene for a fairly long period showed better rehydration with modified Ruffer solution and yield good cellular and nuclear details.

High expression of the autophagy gene Beclin‐1 is associated with favorable prognosis for salivary gland adenoid cystic carcinoma

Although autophagy is universally involved in tumorigenesis and tumor progression, the roles of autophagy and autophagy-regulating genes in salivary gland adenoid cystic carcinoma (ACC) remain unknown. In this study, we investigated the expression of the autophagy-regulating genes Beclin-1, death-associated protein kinase-1, ultraviolet radiation resistance-associated gene, and phosphatase and tensin homolog in salivary gland ACC samples. Immunohistochemistry and real-time polymerase chain reaction were used to analyze the expression of these genes in 89 ACC samples and normal salivary gland tissue samples. The relationship of their expression with clinicopathological features was analyzed. The data showed significantly lower expression of these genes in the tumor samples than in normal salivary gland tissue samples. Furthermore, Beclin-1 expression was significantly correlated with histological pattern of ACC (P<0.05), and high expression of ultraviolet radiation resistance-associated gene was associated with distant metastasis (P<0.05). Most importantly, univariate and multivariate survival analyses suggested that Beclin-1 protein and mRNA expression in cancer cells were independent prognostic indicators for ACC. Our results suggest that autophagy-regulating genes may participate in the pathogenesis of salivary gland ACC. Further research will be required to gain a better understanding of autophagy in ACC.