Adenoid Cystic Carcinoma Cell Research Articles

Nuclear staining for pan-Trk by immunohistochemistry is highly specific for secretory carcinoma of breast: pan-Trk in various subtypes of breast carcinoma

AimsSecretory carcinoma of breast (SCB) typically harbours ETV6-NTRK3 gene fusion. Pan-Trk immunohistochemistry analysis (IHC) has been shown to be sensitive for SCB diagnosis. However, weak focal pan-Trk nuclear staining was...

Pseudonormal Morphology of Salivary Gland Adenoid Cystic Carcinoma Cells Subverts the Antitumor Reactivity of Immune Cells: A Tumour-Cell-Based Initiation of Immune Evasion.

Salivary gland adenoid cystic carcinoma (ACC), mucoepidermoid carcinoma (MEC) and oral squamous cell carcinoma (OSCC) occurs within the head and neck region. So far immune check point inhibitors failed in ACC. Gipie (CCDC88B) is a microtubule linker protein that activates immune cells. Gipie expressions found in head and neck cancer cells. We hypothesised that the presence of Gipie diminishes anti-tumour reactivity of immune cells towards head and neck cancer. To determine the effect of Gipie in oral and salivary gland cancer cells, Gipie was silenced in cancer cells in cancer-immune cells co-culture models and we performed 3D Z series confocal imaging, annexin V and immune activation flow cytometry, proteome profiler and discovery phase proteomics. ACC cells morphed into pseudonormal morphology in immune co-culture models. Silencing Gipie in ACC cells showed significant increase of apoptotic cells and activated natural killer cells, and lowering of regulatory T cells. Other salivary and oral cancer cells showed negligible effect of Gipie. Proteome profiler and proteomics assay confirmed Gipie affecting proliferation mechanism and immune activated proteins in ACC immune co-culture models. Overall, we conclude that the presence of Gipie has a confounding role during the ACC-immune cell interaction.

Beyond mitochondrial transfer, cell fusion rescues metabolic dysfunction and boosts malignancy in adenoid cystic carcinoma

Cancer cells with mitochondrial dysfunction can be rescued by cells in the tumor microenvironment. Using human adenoid cystic carcinoma cell lines and fibroblasts, we find that mitochondrial transfer occurs not only between human cells but also between human and mouse cells both invitro and invivo. Intriguingly, spontaneous cell fusion between cancer cells and fibroblasts could also emerge; specific chromosome loss might be essential for nucleus reorganization and the post-hybrid selection process. Both mitochondrial transfer through tunneling nanotubes (TNTs) and cell fusion "selectively" revive cancer cells, with mitochondrial dysfunction as a key motivator. Beyond mitochondrial transfer, cell fusion significantly enhances cancer malignancy and promotes epithelial-mesenchymal transition. Mechanistically, mitochondrial dysfunction in cancer cells causes L-lactate secretion to attract fibroblasts to extend TNTs and TMEM16F-mediated phosphatidylserine externalization, facilitating TNT formation and cell-membrane fusion. Our findings offer insights into mitochondrial transfer and cell fusion, highlighting potential cancer therapy targets.

Establishment and characterization of cMYB-expressing human salivary adenoid cystic carcinoma cell lines (UM-HACC-14, UM-HACC-6) and matching patient-derived xenograft model (UM-PDX-HACC-14)

Limited availability of authentic human adenoid cystic carcinoma (ACC) cell lines has hindered progress in understanding mechanisms underpinning the biology of this disease and the development of safe and effective therapies. Surgical human ACC specimens (UM-HACC-6, UM-HACC-14) were dissociated into single cell suspensions and cultured in fibronectin-coated flasks. Alternatively, tumor fragments were transplanted subcutaneously into female immunodeficient (SCID) mice to establish patient-derived xenograft tumors (PDX; UM-PDX-HACC-14). Both ACC cell lines showed continuous growth in monolayers for over 100 passages. Total RNA-Seq, RT-PCR, and FISH analysis revealed that both are MYB-NFIB fusion negative. Western blots revealed passage-dependent expression of E-Cadherin, PCNA, p63, phospho-c-MYB, and NFIB. Both, UM-HACC-14 and UM-HACC-6 cells exhibited tumorigenic potential when injected orthotopically into mouse submandibular glands. UM-HACC-14, patient-matching UM-PDX-HACC-14, and the UM-HACC-6 cell line are new, authenticated preclinical models of ACC that are well suited for mechanistic and developmental therapeutics studies.

Tracheal cancer epidemiology and survival trends: A SEER database analysis.

e20078 Background: Tracheal cancer is one of the rarest malignancies of the respiratory system and, hence one of the least studied ones. It has a poor prognosis and understanding its epidemiology can help with effective diagnosis and management. Here we present the Surveillance, Epidemiology, and End Results (SEER) analysis of tracheal cancer. Methods: Information was obtained from the SEER database November 2022 with 17 registries for years 2000-2022. Case selection was done for the Primary labeled site Trachea C 33.9. Only patients with age >20 years and with one primary cancer were included. A total of 537 Patients were analyzed for incidence and survival based on Histology, Age, Gender, Race, Household Income, Area of residence, and treatment received. Results: The most common histology was squamous cell carcinoma (34%),followed by adenoid cystic carcinoma (23%) and Small cell carcinoma (4%). Other histologies (39%) included but were not limited to Large cell carcinoma, adenoid carcinoma, mucoepidermoid carcinoma, etc. The age group studied was 15 years and above. The most common age group affected was 65-69 years (12.3%), closely followed by 60-64 years (12.1%). The mean age of population was 62.5 +/- 14.7 years. Out of the total,56% were males and 44% were females (P value (P) < 0.002). 68.7% of cases were observed in Non-Hispanic Whites, (P <0.0001) followed by Blacks (11.4%), Hispanics (9.3%), Asian/Pacific Islanders (9.9%). 83% of the population was residing in metropolitan versus 17% in non-metropolitan regions (P<0.0001). 38% cases were observed in Annual household Income of >75,000 US dollars (USD) versus 62% in <75,000 USD (P <0.0006). Overall 5-year survival of tracheal cancer was noted to be 27%. Surgery was done in 40% of the cases. Poor 5-year survival was observed in those who did not have surgery compared to those who did(Hazard ratio (HR)=1.45, Confidence Interval (CI) 1.23-1.71, P <0.0001). Radiation was done in 28.1% of cases. Patients who received no radiation therapy had poor outcome compared to those who did. (HR=1.214, CI 1.066-1.383, P <0.0001). White race had worse outcomes compared to other races (HR 1.14, CI 1.003-1.289, P<0.023). The risk of death at 5 years in Males was slightly higher than in females but not statistically significant (HR 1.067, CI 0.96-1.18). Difference was also not significant in those with Household income <75,000 USD compared to those with more than >75,000 USD (HR 0.92 CI 0.83-1.01), Metropolitan versus non-metropolitan areas of residence (P=0.14). Conclusions: Statistically significant improvement in survival has been noted in patients who received the treatments including surgery or radiation in tracheal cancer versus patients who didn’t. Our study suggests that less than half of the patients received surgery and less than one-third of the patients received radiation therapy. Efforts should be made to emphasize the continued utilization of these therapy options for better outcomes.

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.

Extracellular Vesicles Containing circMYBL1 Induce CD44 in Adenoid Cystic Carcinoma Cells and Pulmonary Endothelial Cells to Promote Lung Metastasis.

Adenoid cystic carcinoma (ACC) is a rare malignant epithelial neoplasm that arises in secretory glands and commonly metastasizes to the lungs. MYBL1 is frequently overexpressed in ACC and has been suggested to be a driver of the disease. In this study, we identified a circular RNA (circRNA) derived from MYBL1 pre-mRNA that was accompanied by the overexpression of MYBL1 in ACC. Overexpression of circMYBL1 was correlated with increased lung metastasis and poor overall survival in patients with ACC. Ectopic circMYBL1 overexpression promoted malignant phenotypes and lung metastasis of ACC cells. Mechanistically, circMYBL1 formed a circRNA-protein complex with CCAAT enhancer-binding protein β (CEBPB), which inhibited ubiquitin-mediated degradation and promoted nuclear translocation of CEBPB. In the nucleus, circMYBL1 increased the binding of CEBPB to the CD44 promoter region and enhanced its transcription. In addition, circMYBL1 was enriched in small extracellular vesicles (sEV) isolated from the plasma of patients with ACC. Treatment with sEVs containing circMYBL1 in sEVs enhanced prometastatic phenotypes of ACC cells, elevated the expression of CD44 in human pulmonary microvascular endothelial cells (HPMEC), and enhanced the adhesion between HPMECs and ACC cells. Moreover, circMYBL1 encapsulated in sEVs increased the arrest of circulating ACC cells in the lung and enhanced lung metastatic burden. These data suggest that circMYBL1 is a tumor-promoting circRNA that could serve as a potential biomarker and therapeutic target for ACC. Significance: circMYBL1 stabilizes CEBPB and upregulates CD44 to promote adhesion between cancer cells and endothelial cells and enables lung metastasis of adenoid cystic carcinoma, suggesting that inhibition of this axis could improve patient outcomes.

Anti-Tumor Activity and Mechanism of Silibinin Based on Network Pharmacology and Experimental Verification.

Silibinin is a flavonoid compound extracted from the seeds of Silybum marianum (L.) Gaertn. It has the functions of liver protection, blood-lipid reduction and anti-tumor effects. However, the potential molecular mechanism of silibinin against tumors is still unknown. This study aimed to assess the anti-tumor effects of silibinin in adenoid cystic carcinoma (ACC2) cells and Balb/c nude mice, and explore its potential mechanism based on network pharmacology prediction and experimental verification. A total of 347 targets interacting with silibinin were collected, and 75 targets related to the tumor growth process for silibinin were filtrated. Based on the PPI analysis, CASP3, SRC, ESR1, JAK2, PRKACA, HSPA8 and CAT showed stronger interactions with other factors and may be the key targets of silibinin for treating tumors. The predicted target proteins according to network pharmacology were verified using Western blot analysis in ACC2 cells and Balb/c nude mice. In the pharmacological experiment, silibinin was revealed to significantly inhibit viability, proliferation, migration and induce the apoptosis of ACC2 cells in vitro, as well as inhibit the growth and development of tumor tissue in vivo. Western blot analysis showed that silibinin affected the expression of proteins associated with cell proliferation, migration and apoptosis, such as MMP3, JNK, PPARα and JAK. The possible molecular mechanism involved in cancer pathways, PI3K-Akt signaling pathway and viral carcinogenesis pathway via the inhibition of CASP3, MMP3, SRC, MAPK10 and CDK6 and the activation of PPARα and JAK. Overall, our results provided insight into the pharmacological mechanisms of silibinin in the treatment of tumors. These results offer a support for the anti-tumor uses of silibinin.

Abstract LB022: Preclinical anti-tumorigenic evaluation of AXL targeting antibody-drug-conjugate in an adenoid cystic carcinoma cell line xenograft model

Abstract Adenoid cystic carcinoma (ACC) is a rare type of salivary gland cancer. Despite the many advances made in helping understand the disease behavior and characteristics, the prevailing challenge in managing patients with ACC is the lack of clinically approved systemic therapy drugs to successfully treat those with advanced recurrent or metastatic disease. There are multiple promising candidate agents being evaluated preclinically and in early phase clinical trials, yet an effective drug with consistent overall response remains to be identified. AXL is a member of the TAM family of tyrosine kinase receptors, and its overexpression and activation is generally associated with poor prognosis and chemoresistance in many cancer types. Previous reports show AXL is significantly upregulated in a subset of ACC tumors. Here, we evaluate the tumor growth inhibition effects of a newly developed antibody-drug-conjugate targeting AXL (ADCT-601) in a xenograft ACC cell line model. MDA-ACC-01 cells express high levels of cell surface AXL as confirmed by biochemical analysis. The tumor growth inhibition of MDA-ACC-01 cell xenograft was tested in a single-dose drug administration study. Immunodeficient mice bearing ACC tumors were either injected with vehicle (n=7) or with ADCT-601 at 0.5 (n=9) or 1.0 mg/kg (n=7). ADCT-601 treatment with either 0.5 mg/kg or 1.0 mg/kg resulted in complete response (CR) for all tumor implants. To reaffirm the drug’s efficacy, we challenged the vehicle-treated tumor, prior to exceeding the tumor volume endpoint, with a single-dose of ADCT-601 at 1.0 mg/kg. Strikingly, by day 6 post-treatment, tumor volume began to shrink and eventually resulted in CR except in all but one case. These results demonstrate ADCT-601 is an effective drug with significant anti-tumor activity in our preclinical models and is worthy of additional investigation to determine its translational potential. Citation Format: Joseph O. Humtsoe, Anita Pothukuchi, Hyunseok Kang, Patrick Ha. Preclinical anti-tumorigenic evaluation of AXL targeting antibody-drug-conjugate in an adenoid cystic carcinoma cell line xenograft model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB022.

TGFβ-induced EN1 promotes tumor budding of adenoid cystic carcinoma in patient-derived organoid model.

Adenoid cystic carcinoma (ACC) and basal cell adenoma (BCA) share many histological characteristics and often need a differential diagnosis in clinical pathology. Recently, we found homeobox protein engrailed-1 (EN1) was a potential diagnostic marker for ACC in an organoids library of salivary gland tumors (SGTs). Here we aim to confirm EN1 as a differential diagnostic marker for ACC, and further investigate the regulatory mechanism and biological function of EN1 in tumor progression. The transcriptional analysis, quantitative polymerase chain reaction, Western blot and immunohistochemistry staining were performed and revealed that EN1 was specifically and highly expressed in ACC, and accurately differentiated ACC from BCA. Furthermore, TGFβ signaling pathway was found associated with ACC, and the regulation of EN1 through TGFβ was detected in the human ACC cell lines and patient-derived organoids (PDOs). TGFβ-induced EN1 was important in promoting tumor budding in the PDOs model. Interestingly, a high level of EN1 and TGFβ1 in the budding tips was observed in ACC clinical samples, and the expression of EN1 and TGFβ1 in ACC was significantly associated with the clinical stage. In summary, our study verified EN1 is a good diagnostic marker to differentiate ACC from BCA. TGFβ-induced EN1 facilitates the tumor budding of ACC, which might be an important mechanism related to the malignant phenotype of ACC.

Anti-NOTCH1 therapy with OMP-52 M51 inhibits salivary adenoid cystic carcinoma by depressing epithelial-mesenchymal transition (EMT) process and inducing ferroptosis

Salivary adenoid cystic carcinoma (ACC) is a common type of salivary gland cancer, and the mechanisms underlying its progression still remain poorly understood without efficient therapies. NOTCH1, an evolutionally conserved cell-cell signaling pathway, is involved in the progression of ACC. In our study, we attempted to explore whether NOTCH1 suppression using the monoclonal anti-NOTCH1 antibody OMP-52 M51 could be of potential for ACC treatment. Here, we identified NOTCH1 elevation in human ACC tissues compared with the matched normal samples. Patients with metastasis expressed much higher NOTCH1. We then found that OMP-52 M51 markedly reduced the expression of NOTCH1 and its intracellular active form NICD1 (NOTCH1 intracellular domain). Importantly, OMP-52 M51 markedly reduced the proliferation, migration and invasion of ACC cells. RNA-Seq and in vitro studies further showed that OMP-52 M51 significantly induced ferroptosis in ACC cells, indicated by the increased cellular malondialdehyde (MDA), iron contents and lipid ROS production, and decreased glutathione (GSH) levels. Further, remarkable glutathione peroxidase 4 (GPX4) reduction was detected in ACC cells with OMP-52 M51 treatment. However, promoting NOTCH1 expression markedly abolished the function of OMP-52 M51 to induce ferroptosis. Intriguingly, low-dose OMP-52 M51 strongly facilitated the capacity of ferroptosis inducer erastin to trigger ferroptotic cell death, revealing that OMP-52 M51 could improve the sensitivity of ACC cells to ferroptosis. In vivo, OMP-52 M51 administration suppressed tumor growth and induced ferroptosis in the constructed ACC xenograft mouse model. Collectively, our findings demonstrated that NOTCH1 inhibition by OMP-52 M51 represses the proliferation and epithelial-mesenchymal transition (EMT) in ACCs, and promotes ferroptosis, revealing the potential therapeutical application of OMP-52 M51 in ACC.

Wnt/β-catenin-C-kit axis may play a role in adenoid cystic carcinoma prognostication

Adenoid cystic carcinoma (ACC) is one of the most common malignant salivary gland tumors. ACC is composed of myoepithelial and epithelial neoplastic cells which grow slowly and have a tendency for neural invasion. The long term prognosis is still relatively poor. Although several gene abnormalities, such as fusions involving MYB or MYBL1 oncogenes and the transcription factor gene NFIB, and overexpression of KIT have been reported in ACC, their precise functions in the pathogenesis of ACC remain unclear. We recently demonstrated that the elevated expression of Semaphorin 3A (SEMA3A), specifically expressed in myoepithelial neoplastic cells, might function as a novel oncogene-related molecule to enhance cell proliferation through activated AKT signaling in 9/10 (90%) ACC cases. In the current study, the patient with ACC whose tumor was negative for SEMA3A in the previous study, revisited our hospital with late metastasis of ACC to the cervical lymph node eight years after surgical resection of the primary tumor. We characterized this recurrent ACC, and compared it with the primary ACC using immunohistochemical methods. In the recurrent ACC, the duct lining epithelial cells, not myoepithelial neoplastic cells, showed an elevated Ki-67 index and increased cell membrane expression of C-kit, along with the expression of phosphorylated ERK. Late metastasis ACC specimens were not positive for β-catenin and lymphocyte enhancer binding factor 1 (LEF1), which were detected in the nuclei of perineural infiltrating cells in primary ACC cells. In addition, experiments with the GSK-3 inhibitor revealed that β-catenin pathway suppressed not only KIT expression but also proliferation of ACC cells. Moreover, stem cell factor (SCF; also known as KIT ligand, KITL) induced ERK activation in ACC cells. These results suggest that inactivation of Wnt/β-catenin signaling may promote C-kit-ERK signaling and cell proliferation of in metastatic ACC.

Clinical features and prognostic factors for malignant parotid tumors in children and adolescents: A population-based study

PurposeWe performed a population-based cohort study to investigate the clinical characteristics and survival rates of primary malignant parotid tumors (MPT) in children and adolescents. MethodsThe Surveillance, Epidemiology, and End Results (SEER) database was used to identify all pediatric and adolescent patients with MPT who were diagnosed between 2000 and 2018. Based on a number of parameters, survival curves were produced using Kaplane-Meier estimates. The log-rank test was used to compare survival curves. The influence of each component on overall survival (OS) was examined using a multivariate Cox proportional hazards model. ResultsThere were 352 identified pediatric and adolescent patients with MPT. At diagnosis, the age ranged from 1.0 to 19 years, with a median of 15 years. Mucoepidermoid carcinoma (MC) (46.5 %) was the most common histological subtype, followed by acinar cell carcinoma (ACC) (36.4 %) and others (17.1 %) such as adenoid cystic carcinoma and squamous cell carcinoma. All patients had overall survival rates of 98.8 %, 95.6 %, and 94.6 % at 1-year, 3-year and 5-year, respectively. The results of the Cox proportional hazard regression showed that tumor grade, SEER stage, radiotherapy, and treatment regimens were significant independent predictors of overall survival. ConclusionsIn pediatric and adolescent MPT, tumor grade, SEER stage, adjuvant radiation, and treatment regimens were found to be important independent predictors of survival. More research is required to validate the role of adjuvant radiation.

Defining the relationship of salivary gland malignancies to novel cell subpopulations in human salivary glands using single nucleus RNA-sequencing.

Salivary glands have essential roles in maintaining oral health, mastication, taste and speech, by secreting saliva. Salivary glands are composed of several types of cells, and each cell type is predicted to be involved in the carcinogenesis of different types of cancers including adenoid cystic carcinoma (ACC), acinic cell carcinoma (AciCC), salivary duct carcinoma (SDC), myoepithelial carcinoma (MECA) and other histology. In our study, we performed single nucleus RNA-seq on three human salivary gland samples to clarify the gene expression profile of each complex cellular component of the salivary glands and related these expression patterns to expression found in salivary gland cancers (SGC) to infer cell of origin. By single nucleus RNA-seq, salivary gland cells were stratified into four clusters: acinar cells, ductal cells 1, ductal cells 2 and myoepithelial cells/stromal cells. The localization of each cell group was verified by IHC of each cluster marker gene, and one group of ductal cells was found to represent intercalated ductal cells labeled with HES1. Furthermore, in comparison with SGC RNA-seq data, acinar cell markers were upregulated in AciCC, but downregulated in ACC and ductal cell markers were upregulated in SDC but downregulated in MECA, suggesting that markers of origin are highly expressed in some SGC. Cell type expressions in specific SGC histology are similar to those found in normal salivary gland populations, indicating a potential etiologic relationship.

Preclinical 3D-model supports an invisibility cloak for adenoid cystic carcinoma

The tumour-cell based initiation of immune evasion project evaluated the role of Gipie in adenoid cystic carcinoma (ACC) and mucoepidermoid carcinoma (A-253), from ninety-six 3D-ACC and A-253-immune co-culture models using natural killer cells (NK), and Jurkat cells (JK). Abnormal ACC morphology was observed in 3D-ACC immune co-culture models. Gipie-silencing conferred a “lymphoblast-like” morphology to ACC cells, a six-fold increase in apoptotic cells (compared to unaltered ACC cells, P ≤ 0.0001), a two-fold decrease in T regulatory cells (FoxP3+/IL-2Rα+/CD25+) (P ≤ 0.0001), and a three-fold increase in activated NK cells (NKp30+/IFN-γ+) (P ≤ 0.0001) with significantly higher release of granzyme (P ≤ 0.001) and perforin (P ≤ 0.0001).

Cell-type-specific tumour sensitivity identified with a bromodomain targeting PROTAC in adenoid cystic carcinoma.

Salivary gland adenoid cystic carcinoma (ACC) is a rare malignancy with limited treatment options. The development of novel therapies is hindered by a lack of preclinical models. We have generated ACC patient-derived xenograft (PDX) lines that retain the physical and genetic properties of the original tumours, including the presence of the common MYB::NFIB or MYBL1::NFIB translocations. We have developed the conditions for the generation of both 2D and 3D tumour organoid patient-derived ACC models that retain MYB expression and can be used for drug studies. Using these models, we show in vitro and in vivo sensitivity of ACC cells to the bromodomain degrader, dBET6. Molecular studies show a decrease in BRD4 and MYB protein levels and target gene expression with treatment. The most prominent effect of dBET6 on tumours in vivo was a change in the relative composition of ACC cell types expressing either myoepithelial or ductal markers. We show that dBET6 inhibits the progenitor function of ACC cells, particularly in the myoepithelial marker-expressing population, revealing a cell-type-specific sensitivity. These studies uncover a novel mechanistic effect of bromodomain inhibitors on tumours and highlight the need to impact both cell-type populations for more effective treatments in ACC patients. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

The Role of Novel Immunohistochemical Markers for Special Types of Breast Carcinoma.

Some histologic special types of breast carcinoma harbor specific recurrent genetic alterations that are not seen in other types of breast carcinoma (no special type), namely adenoid cystic carcinoma, secretory carcinoma, and tall cell carcinoma with reversed polarity. These tumors have unique morphologic features, are triple-negative, that is, do not express hormone receptors or HER2, and are generally associated with a favorable prognosis. Adenoid cystic carcinoma, like its counterpart in other organs, shows a MYB-NFIB fusion gene that is the result of a recurrent t(6;9)(q22-23;p23-24) translocation. Other MYB alterations have been described that result in overexpression of MYB . Secretory carcinoma is characterized by an ETV6-NTRK3 gene fusion that is the result of recurrent (12;15);(p13;q25) translocation, which is also seen in mammary analog secretory carcinoma of the salivary gland. Tall cell carcinoma with reversed polarity shows IDH2 p.Arg172 hotspot mutations. Immunohistochemical antibodies have emerged that identify the underlying genetic alterations in these tumors and serve as useful diagnostic tools. This review will provide an update on the molecular features and diagnostic immunohistochemical markers that have become increasingly popular to aid in diagnosing these uncommon triple-negative breast tumors.

Abstract PO-071: Pseudonormal morphology of adenoid cystic carcinoma cells subverts the antitumor reactivity of immune cells

Abstract Objectives: Adenoid cystic carcinoma (ACC) is a rare salivary gland cancer most frequently arising in the head and neck region. The ACC microenvironment exhibits low immunogenicity (low tumor infiltrating lymphocytes and dendritic cells). This scenario favours immune evasion and partially explains poor prognosis because of the activation of immune inhibitory proteins. Gipie is a hook-related protein, that is involved in protein trafficking. Gipie (HkRP3, encoded by CCDC88B) is associated with T cell maturation and inflammatory functions and target cell killing in natural killer (NK) cells. Gipie is present in ACC patient samples and cells. Therefore, we investigated proliferation, apoptosis, and morphologic changes caused by Gipie in oral and salivary gland cancer cells in presence of immune cells. Methods: We assayed UM-HACC-2A (adenoid cystic carcinoma), A-253 (mucoepidermoid carcinoma, MEC), SCC4, SCC9, SCC25, CAL27 (oral squamous cell carcinoma, OSCC), OKF6 (normal oral) cells cocultured with, NK-92 (natural killer), and Jurkat, Clone E6-1 (acute T cell leukemia) cells, to construct multiple salivary gland and oral cancer-immune cell co-culture models. Gipie silenced cancer cells (silencing maintained for 48 hours) in the cancer immune coculture models were compared with their unaltered subsets. Cancer-immune cells interactions were maintained for 16 hours. Overall three hundred thirty-six (336) co-culture models were used to determine apoptosis, immune activation, morphology, transmigration, and protein expression. Additionally, we performed targeted mass spectrometry analysis to identify changes in protein profiles. Results: ACC cells exhibited Pseudonormal morphology after interacting with immune cells in the 3D coculture model. Gipie-silenced ACC cells in coculture model transformed to “lymphoblast-like” morphology. Gipie-silenced ACC cells in co-culture model (n = 24) showed significant increase of apoptotic cells compared to unaltered ACC cells, lowering of T regulatory cells (FoxP3+/IL-2Rα+/CD25+) (n = 24), and increase of activated NK cells (NKp30+/IFN-γ+) (n = 24) with significantly higher release of granzyme (n = 12) and perforin (n = 12). Increased activation of immune cells (transmigration and fluorescence intensity) via 3D-z-stack images were observed in Gipie-silenced subsets (n = 24). MEC cells responses were significantly less compared to ACC in co-culture models followed by silencing of Gipie, while OSCC and OKF6 cell responses were negligible, under identical conditions. Conclusions: The presence of Gipie confers pseudonormal morphology to ACC cells thereby reducing immune attack. Thus, trafficking proteins may impact ACC cancer-immune cell interaction during conventional chemotherapy or monoclonal immunotherapy. Citation Format: Rajdeep Chakraborty, Charbel Darido, Giuseppe Palmisano, Arthur Chien, Aidan Tay, Thiri Zaw, Shoba Ranganathan. Pseudonormal morphology of adenoid cystic carcinoma cells subverts the antitumor reactivity of immune cells [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-071.

Basal cell adenoma of parotid gland: two case reports and literature review.

Most of salivary tumors are benign in nature and are typically diagnosed and classified based on their histopathological presentation. Basal cell adenoma of the salivary glands is a rare, benign disease accounting for 1% to 3% of salivary gland tumors. Despite its low incidence, basal cell adenoma is the third most common benign tumor of the salivary gland after pleomorphic adenoma and Warthin's tumor. It usually appears as a firm and slow-growing mass. Due to the prognosis, differential diagnosis with basal cell adenocarcinoma, adenoid cystic carcinoma and basaloid squamous cell carcinoma is required. In this report, we present two cases; a 62-year-old woman who presented with an asymptomatic, and slow-growing mass and a 64-year-old woman with a static-sized mass in the parotid gland. In both cases, the mass was completely excised, postoperative pathology reports confirmed the diagnosis of basal cell adenoma. We also review the literature and discuss this rare entity.

Therapeutic inhibition of Bmi-1 ablates chemoresistant cancer stem cells in adenoid cystic carcinoma

ObjectivesAdenoid Cystic Carcinomas (ACC) typically show modest responseto cytotoxic therapy. Cancer stem cells (CSC) have been implicated in chemoresistance and tumor relapse. However, their role in ACC remains unknown. The purpose of this work was to evaluate the impact of targeting ACC CSCs with Bmi-1 inhibitors on resistance to cytotoxic therapy and tumor relapse. Materials and methodsTherapeutic efficacy of a small molecule inhibitor of Bmi-1 (PTC596; Unesbulin) and/or Cisplatin on ACC stemness was evaluated in immunodeficient mice harboring PDX ACC tumors (UM-PDX-HACC-5) and in human ACC cell-lines (UM-HACC-2A,-14) or low passage primary human ACC cells (UM-HACC-6). The effect of therapy on stemness was examined by salisphere assays, flow cytometry for ALDH activity and CD44 expression, and Western blots for Bmi-1 (self-renewal marker) and Oct4 (embryonic stem cell marker) expression. ResultsPlatinum-based agents (Cisplatin, Carboplatin) induced Bmi-1 and Oct4 expression, increased salisphere formation and the CSC fraction in vitro and in vivo. In contrast, PTC596 inhibited expression of Bmi-1, Oct4 and pro-survival proteins Mcl-1 and Claspin; decreased the number of salispheres, and the fraction of ACC CSCs in vitro. Silencing Claspin decreased salisphere formation and CSC fraction. Both, single agent PTC596 and PTC596/Cisplatin combination decreased the CSC fraction in PDX ACC tumors. Notably, short-term combination therapy (2 weeks) with PTC596/Cisplatin prevented tumor relapse for 150 days in a preclinical trial in mice. ConclusionTherapeutic inhibition of Bmi-1 ablates chemoresistant CSCs and prevents ACC tumor relapse. Collectively, these results suggest that ACC patients might benefit from Bmi-1-targeted therapies.