Intratumoral microbiome of adenoid cystic carcinomas and comparison with other head and neck cancers.

Adenoid cystic carcinoma (ACC) is a rare, usually slow-growing yet aggressive head and neck malignancy. Despite its clinical significance, our understanding of the cellular evolution and microenvironment in ACC remains limited. We investigated the intratumoral microbiomes of 50 ACC tumor tissues and 33 adjacent normal tissues using 16S rRNA gene sequencing. This allowed us to characterize the bacterial communities within the ACC and explore potential associations between the bacterial community structure, patient clinical characteristics, and tumor molecular features obtained through RNA sequencing. The bacterial composition in the ACC was significantly different from that in adjacent normal salivary tissue, and the ACC exhibited diverse levels of species richness. We identified two main microbial subtypes within the ACC: oral-like and gut-like. Oral-like microbiomes, characterized by increased diversity and abundance of Neisseria, Leptotrichia, Actinomyces, Streptococcus, Rothia, and Veillonella (commonly found in healthy oral cavities), were associated with a less aggressive ACC-II molecular subtype and improved patient outcomes. Notably, we identified the same oral genera in oral cancer and head and neck squamous cell carcinomas. In both cancers, they were part of shared oral communities associated with a more diverse microbiome, less aggressive tumor phenotype, and better survival that reveal the genera as potential pancancer biomarkers for favorable microbiomes in ACC and other head and neck cancers. Conversely, gut-like intratumoral microbiomes, which feature low diversity and colonization by gut mucus layer-degrading species, such as Bacteroides, Akkermansia, Blautia, Bifidobacterium, and Enterococcus, were associated with poorer outcomes. Elevated levels of Bacteroides thetaiotaomicron were independently associated with significantly worse survival and positively correlated with tumor cell biosynthesis of glycan-based cell membrane components.

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.

Letter to editor: Comment on "Clinical disease course and survival outcomes following disease recurrence in adenoid cystic carcinoma with and without NOTCH signaling pathway activation".

The study by Feeney et al. provides critical insights into the prognostic implications of NOTCH pathway activation in adenoid cystic carcinoma (ACC), particularly after disease recurrence. Utilizing both next-generation sequencing and immunohistochemistry, the research delineates the survival outcomes between NOTCH-activated and non-activated ACC groups, highlighting poorer outcomes in the former. The findings advocate for the targeted therapeutic approach and suggest a potential for personalized treatment strategies, emphasizing the need for further research into NOTCH pathway inhibitors and their clinical applications.

Solitary liver metastasis from adenoid cystic carcinoma of the submandibular gland.

Adenoid cystic carcinoma (ACC) is a rare tumour of the salivary glands characterised by distant metastases, mainly to lungs and bone. Isolated metastasis to the liver is unusual. We present the case of a woman with an ACC of the submandibular gland (pT1N0) who underwent radical submandibular gland excision and selective neck dissection. Preoperative imaging identified a liver lesion with features suggestive of a haemangioma. Two-year postoperatively, a surveillance CT neck/trunk showed an increase in size of the left liver lobe lesion. Subsequent MR liver and US-guided biopsy confirmed the lesion to be metastatic ACC. The patient underwent a successful left lateral liver sectionectomy. She remains disease-free 2.5 years after her liver resection. A literature search revealed only four other similar cases. This report highlights that even early-stage ACCs of the salivary gland may present with synchronous solitary liver metastasis which can be effectively treated with curative surgery.

[Comparison of 5-year survival rate and analysis of prognostic factors influencing the prognosis of adenoid cystic carcinoma and squamous cell carcinoma of the maxillary sinus: based on the SEER database].

Objective:To analyze the difference in 5-year survival between maxillary sinus adenoidal cystic carcinoma（maxillary sinus adenoid cystic carcinoma, MSACC） and squamous cell carcinoma（maxillary sinus squamous cell carcinoma, MSSCC） using the National Cancer Institute's Surveillance, Epidemiology, and End. Results:database（SEER） and to explore the factors associated with the prognosis of the two tumors. Methods:The data of 161 patients with MSACC and 929 patients with MSSCC were collected from SEER database, and the 5-year overall survival rate（OS） and tumor specific survival rate（CSS） were compared between the two groups before and after propensity score matching. The forest map of multivariate Cox proportional hazard regression model was established to analyze the prognostic factors affecting the survival rate of patients with MSACC and MSSCC. Results:There were statistical differences in 5-year OS and CSS between MSACC and MSSCC before and after propensity score matching（P<0.001）. Multivariate regression analysis showed that age, side of the disease, lymph node metastasis, operation and radiotherapy were the influencing factors of OS in MSACC, while age and operation were the influencing factors of CSS. Age, race, T grade, lymph node metastasis, systemic metastasis, surgery, radiotherapy and chemotherapy are the influencing factors of OS of MSSCC. Age, T grade, lymph node metastasis, systemic metastasis, surgery, radiotherapy and chemotherapy are the influencing factors of CSS. Conclusion:The 5-year survival rate of MSACC is higher than that of MSSCC. Surgery plays a positive role in the prognosis of the two kinds of tumors. The analysis results can provide some reference for their survival expectations and treatment choices.

Differential Expression of Mucin in Salivary Gland Tumours.

Background and Objectives: Mucin has been implicated via various mechanisms in the development and growth of tumour cells. However, mucin expression studies in salivary gland tumours are limited, especially with samples from minor salivary glands. This study aims to investigate and compare mucin expression in benign and malignant salivary gland tumours of minor and major salivary gland origins. Materials and Methods: Special stains were used to stain neutral mucin (Periodic acid Schiff), sialomucin (Alcian Blue) and sulfomucin (Aldehyde Fuschin) within tissues from six normal salivary glands and 73 salivary gland tumours including 31 pleomorphic adenomas, 27 mucoepidermoid carcinomas, and 15 adenoid cystic carcinomas. A semi-quantitative approach was used to evaluate mucin expression within ductal lumens. Sialomucin was the most expressed mucin in all salivary gland tumours, regardless of origin. Results: A significant difference was observed in the mucin expression between benign and malignant salivary gland tumours, as pleomorphic adenoma showed three times significantly higher expression of sialomucin compared to mucoepidermoid carcinoma and adenoid cystic carcinoma (p = 0.028). Pleomorphic adenomas of major glands showed 42 times significantly higher expression of sialomucin compared to those of minor glands (p = 0.000). Conclusions: Sialomucin content in pleomorphic adenomas of major glands was vastly increased compared to that in minor glands. Differential sialomucin expression in benign and malignant salivary gland tumours suggests a role in diagnosing of borderline salivary gland tumours.

Is epithelial-mesenchymal transition related to the biological behavior of salivary gland neoplasms?

OBJECTIVE: To evaluate and compare the expression of E-cadherin, Snail1 and Twist1 in pleomorphic adenomas (PAs), adenoid cystic carcinomas (AdCCa) and carcinoma ex-pleomorphic adenomas (CaexPA) of salivary glands, as well as investigate possible associations with clinicopathological parameters. STUDY DESIGN: E-cadherin, Snail1 and Twist1 antibody immunostaining were analyzed semiquantitatively in 20 PAs, 20 AdCCas and 10 CaexPAs. Cases were classified as low and high expression for analysis of the association with clinicopathological parameters. RESULTS: Compared to PAs, AdCCas and CaexPAs exhibited higher nuclear expression of Snail1 (p = 0.021 and p = 0.028, respectively) and Twist1 (p = 0.009 and p = 0.001). Membranous and cytoplasmic expression of E-cadherin were positively correlated in PAs, AdCCas and CaexPAs (r = 0.645, p = 0.002; r = 0.824, p < 0.001; r = 0.677, p = 0.031). In PAs, positive correlation was found between nuclear expression of Snail1 and membrane expression of E-cadherin (r = 0.634; p = 0.003), as well as between nuclear expression of Snail1 and Twist1 (r = 0.580; p = 0.007). Negative correlations were detected between membrane expression of E-cadherin and cytoplasmic expression of Snail1 in AdCCas (r = - 0.489; p = 0.029). CONCLUSIONS: E-cadherin, Twist1, and Snail1 may participate in modulating events related to cell differentiation and adhesion in PAs and to biological behavior in AdCCas and CaexPAs, which indicates the involvement of EMT in these processes. Furthermore, the expression of these proteins in these carcinomas may reflect the plasticity feature of EMT.

A Novel Scoring System for MYB RNA In Situ Hybridization Displays High Sensitivity and Specificity for Adenoid Cystic Carcinoma in a Clinical Setting.

BACKGROUND: MYB RNA in situ hybridization (ISH) has emerged as a reliable and accessible marker to support adenoid cystic carcinoma (ACC) diagnosis, though still not well studied. Here, we report our results in a validation and prospective cohort to improve MYB RNA ISH diagnostic accuracy. METHODS: 79 cases (23 retrospective and 56 prospective) underwent MYB RNA ISH testing (44 ACC and 35 non-ACC). MYB RNA ISH results were initially interpreted based on previously established (original) scoring criteria. Weighted "i-scores", percent positive tumor cells, percent tumor cells with large signals (% LS), and staining pattern (abluminal, diffuse, focal non-patterned, or negative) were inputs for logistic regression models. Final model performance characteristics were compared with original scoring criteria and MYB::NFIB FISH results. RESULTS: An abluminal pattern was characteristic and exclusive to ACC. All i-scores, % LS, and percent positive were significantly higher in ACC. Original scoring criteria yielded a 95.5% sensitivity (Sn), 68.6% specificity (Sp), and 83.5% accuracy. MYB::NFIB FISH yielded a 42.9% sensitivity, 100% specificity, and 60% accuracy. Optimizing for performance, simplicity, and minimal collinearity, our final model was defined as: abluminal pattern and/or % LS > 16.5%, which resulted in a 93.2% Sn, 97.1% Sp, and 94.9% accuracy for ACC diagnosis. False negatives included an ACC with striking tubular eosinophilia and a MYBL1::NFIB translocated ACC. One false positive exclusive to the final model was a nasopharyngeal carcinoma with MYB amplification. CONCLUSIONS: MYB RNA ISH has a higher Sn than MYB::NFIB FISH while retaining high Sp. Our model provides improvements to specificity compared to original scoring criteria and highlight the importance of abluminal staining pattern and % LS. Nonetheless, alternate fusions remain key false negatives while rare non-ACC with other mechanisms of MYB activation may present as false positives.

Adenoid Cystic carcinoma of minor salivary glands (AdCCmSG): a multidisciplinary update.

INTRODUCTION: Adenoid cystic carcinoma of minor salivary glands (AdCCmSG) represents a 'rarity in the rarity,' posing a clinical challenge in lack of standardized, evidence-based recommendations. At present, AdCCmSG management is mostly translated from major salivary gland cancers (MSGCs). Ideally, AdCCmSG diagnostic-therapeutic workup should be discussed and carried out within a multidisciplinary, high-expertise setting, including pathologists, surgeons, radiation oncologists and medical oncologists. AREAS COVERED: The present review provides an overview of epidemiology and pathologic classification. Moreover, the most recent, clinically relevant updates in the treatment of AdCCmSG (Pubmed searches, specific guidelines) are critically discussed, aiming to a better understanding of this rare pathologic entity, potentially optimizing the care process, and offering a starting point for reflection on future therapeutic developments. EXPERT OPINION: The management of rare cancers is often hindered by limited data and clinical trials, lack of evidence-based guidelines, and hardly represented disease heterogeneity, which cannot be successfully tackled with a 'one-size-fits-all' approach. Our goal is to address these potential pitfalls, providing an easy-to-use, updated, multidisciplinary collection of expert opinions concerning AdCCmSG management as of today's clinical practice. We will also cover the most promising future perspectives, based on the potential therapeutic targets highlighted within AdCCmSG's molecular background.

Long-term outcomes after particle radiation therapy in patients with nasopharyngeal adenoid cystic carcinoma.

BACKGROUND: Nasopharyngeal adenoid cystic carcinoma (NACC) is a relatively rare salivary gland tumor that is generally associated with poor outcomes. High-dose radiotherapy is a key treatment for patients with NACC. This study reported the long-term efficacy and safety of particle beam radiation therapy (PBRT) for NACC. METHODS AND MATERIALS: Twenty-six patients with nonmetastatic NACC who received definitive PBRT alone were included in this retrospective study. The majority of patients (92.3%) had locally advanced disease. Twenty-five (96.15%) patients received intensity-modulated proton radiotherapy (IMPT) followed by a carbon ion radiotherapy (CIRT) boost, and one patient received CIRT alone. Overall survival (OS), local control (LC), regional control (RC), and distant metastasis control (DMC) rates were calculated via the Kaplan-Meier method. RESULTS: The median follow-up time was 46.95 months for the entire cohort. Seven patients experienced local recurrence, and one patient experience neck lymph node recurrence. The 3- and 4-year OS, LC, RC, and DMC rates were 100% and 91.7%, 92.3% and 84.6%, 95.8% and 87.8%, and 90.2% and 71.3%, respectively. A total of 91.3% of the patients achieved complete remission of gross tumors at 1 year after PBRT. Severe acute toxicity was observed in only two patients. A grade 4 decrease in visual acuity was observed in one patient with orbital apex invasion. No late grade 3 or 5 toxicity was observed. CONCLUSION: Definitive PBRT provided a satisfactory 4-year OS for patients with locally advanced NACC. The toxicity was acceptable and mild. Further follow-up is necessary to confirm the efficacy and safety of definitive PBRT for patients with NACC.

Metastatic Adenoid Cystic Carcinoma of the Bartholin Gland.

ABSTRACT: Adenoid cystic carcinoma (ACC) of the Bartholin gland is an exceedingly rare neoplasm. A 56-year-old woman with remote ACC resection (plus neoadjuvant chemoradiation and adjuvant chemotherapy) presented to an outside institution with shortness of breath. CT showed bilateral pulmonary nodules and mediastinal lymphadenopathy. With high clinical suspicion for metastatic disease, 18 F-FDG PET/CT was performed and showed scattered nodules with mild FDG uptake along with FDG-avid mediastinal, bilateral hilar, and bilateral cervical chain lymphadenopathy. Lung biopsy of a hypermetabolic nodule confirmed metastatic ACC.

PD-L1 and PD-L2 Expression in Different Tumor Stages and Types of Malignant Salivary Gland Neoplasms: A Single-center Experience.

There is a limited amount of data on the role of programmed cell death ligand (PD-L) -1 and PD-L2 in salivary gland carcinomas. We aimed to evaluate the prognostic value of PD-L1 and PD-L2 expressions, which are closely related to immune mechanisms, with respect to salivary gland tumor types and stages. Data from patients with salivary gland masses surgically removed between 2006 and 2021, diagnosed with a malignant salivary gland neoplasm, were retrospectively analyzed. Immunoreactivity for PD-L1 and PD-L2 was performed on resection materials. The mean age of 90 patients was 52.1±18.8 and 46.7% were male. Overall, 55.6% of patients were diagnosed with adenoid cystic carcinoma (ACC), 23.3% with mucoepidermoid carcinoma (MEC), 16.7% with acinic cell carcinoma (AciCC), 3.3% with ductal carcinoma (DC), and 1 patient with pleomorphic adenoma ex carcinoma (PA-ex-CA). In all, 52% of ACC, 12% of AciCC, 24% of MEC, and 12% of DC cases were at stage IV. The tumor diameter, frequencies of lymphovascular invasion, metastasis, positive surgical margin, recurrence, and mortality rates of patients at stages III and IV were significantly larger than those at stages I and II ( P <0.05). The percentages of tumor cell score (TCS) and immune cell score (ICS) for PD-L1 were significantly higher among patients with MEC compared with those with other types of tumors ( P =0.0011). However, the percentages of combined score (CS) for PD-L1 and tumor cell score for PD-L2 were comparable among tumor types ( P >0.05). No significant difference was found in these scores for PD-L1 between tumor stages ( P >0.05), but for PD-L2, all patients at stage I had TCS <1% for PD-L2, while all patients at stages II and III, and 92% of patients at stage IV had TCS ≥1% ( P <0.0001). High expression of PD-L1 was mostly observed in MEC cases ( P =0.0016), while all patients with AciCC had a low PD-L1 expression level ( P =0.0206). The mean tumor diameter, rate of lymphovascular invasion, perineural invasion, metastasis, positive surgical margin, recurrence, type of treatment, mortality, and TILs ratio did not differ significantly according to PD-L1 expression level ( P >0.05). The percentage of tumor-infiltrating lymphocytes was comparable among negative and positive PD-L1 scores according to both 1% and 5% threshold values ( P >0.05). High PD-L1 expression is rare in AciCC, while PD-L1 expression is high in MEC. Our findings underline the importance of future screening for PD-L1 and PD-L2 before patients undergoing immunotherapies in all salivary gland tumors.

Case series on the management and outcomes of Bartholin gland carcinoma.

OBJECTIVE: To evaluate the management and outcomes of Bartholin gland cancer at a single tertiary institution. STUDY DESIGN: A single institution retrospective review of 9 cases of BGC between 2004 and 2022 was conducted. Demographics, pathological characteristics, treatment, follow up and oncologic outcomes were extracted from clinical records. Data are summarised using descriptive statistics and survival probabilities are presented with Kaplan Meier graphs. RESULTS: Ten cases of BGC were identified at our institution over a period of 18 years. Nine out of ten clinical records were available for analysis. Eight patients presented with vulval swelling and four were treated initially for Bartholin cyst or abscess. One patient had a histological diagnosis of adenoid cystic carcinoma while the remaining were squamous cell carcinomas. With the exception of stage I disease chemoradiation was the primary mode of treatment. Adverse events included skin desquamation (4/9), venous thrombo-embolism (2/9), gastro-intestinal (1/9) and neurotoxicity (1/9). Median follow up was 60 months with a 5-year recurrence free and overall survival at 76 % and 64 % respectively. CONCLUSION: BGC may present after a long duration of symptoms and at advanced stages. Primary chemoradiation appears to be a feasible treatment option in advanced disease with the benefit of decreased morbidity.

White out hemithorax secondary to salivary gland type of lung cancer with metastasis in liver and bone: a case report.

BACKGROUND: Salivary gland-type lung carcinomas are uncommon neoplasms of the lung, representing less than 1% of all lung tumors. The two most common among them are adenoid cystic carcinoma and mucoepidermoid carcinoma. Although they usually have an indolent behavior, adenoid cystic carcinomas can be more aggressive, with 5-year survival as low as 55%. Very few cases are reported in literature. We report a similar rare case of salivary gland type lung carcinoma that presented for the first time with unilateral opacification of left hemithorax. CASE PRESENTATION: A 38-year-old man of North Indian origin, who was a a nonsmoker, presented with complaints of shortness of breath and cough for 1 year, which has increased in the last 2 months and was associated with significant weight loss. A frontal radiograph of the chest and computed tomography of the chest were performed, which showed a mass in the left upper lobe of the lung with its epicenter in the left main bronchus. A bronchoscopic guided biopsy was performed, and histopathology confirmed the diagnosis of lung carcinoma of salivary gland type (adenoid cystic carcinoma). There was invasion of major vessels, hence the patient was offered and started on palliative management instead of surgical treatment. In spite of palliative management of two cycles of chemotherapy and radiotherapy, the patient succumbed to the disease within 2 months from the time of diagnosis. CONCLUSION: Lung carcinoma of the salivary gland type (especially adenoid cystic carcinoma) usually presents at a later stage. The resectability of the tumor depends on the involvement of the surrounding major vessels. Interestingly, these cancers have no association with smoking. The prognosis depends on the extent of the disease at the time of diagnosis. Hence, imaging plays a major role in deciding the further plan of management.