Presence of Fusobacterium nucleatum in relation to patient survival and an acidic environment in oesophagogastric junction and gastric cancers.

BACKGROUND: Fusobacterium nucleatum inhabits the oral cavity and affects the progression of gastrointestinal cancer. Our prior findings link F. nucleatum to poor prognosis in oesophageal squamous cell carcinoma via NF-κB pathway. However, its role in oesophagogastric junction and gastric adenocarcinoma remains unexplored. We investigated whether F. nucleatum influences these cancers, highlighting its potential impact. METHODS: Two cohorts of EGJ and gastric adenocarcinoma patients (438 from Japan, 380 from the USA) were studied. F. nucleatum presence was confirmed by qPCR, FISH, and staining. Patient overall survival (OS) was assessed based on F. nucleatum positivity. EGJ and gastric adenocarcinoma cell lines were exposed to F. nucleatum to study molecular and phenotypic effects, validated in xenograft mouse model. RESULTS: In both cohorts, F. nucleatum-positive EGJ or gastric adenocarcinoma patients had notably shorter OS. F. nucleatum positivity decreased in more acidic tumour environments. Cancer cell lines with F. nucleatum showed enhanced proliferation and NF-κB activation. The xenograft model indicated increased tumour growth and NF-κB activation in F. nucleatum-treated cells. Interestingly, co-occurrence of F. nucleatum and Helicobacter pylori, a known risk factor, was rare. CONCLUSIONS: F. nucleatum can induce the NF-κB pathway in EGJ and gastric adenocarcinomas, leading to tumour progression and poor prognosis.

Three biomarkers (HER2, PD-L1, and microsatellite status) in a large cohort of metastatic gastroesophageal adenocarcinomas: The MD Anderson Cancer Center experience.

Human epidermal growth factor receptor-2 (HER2), programmed death-ligand 1 (PD-L1), and microsatellite (MS) status are well-established biomarkers in gastroesophageal adenocarcinomas (GEAs). However, it is unclear how the combination of these biomarkers is associated with clinicopathological factors and prognosis. This retrospective study included baseline metastatic GEA patients who were tested for all three biomarkers (HER2, PD-L1, and MS status) at the MD Anderson Cancer Center between 2012 and 2022. Stratification was performed according to the combination of biomarker profiles: triple negative (TN), single positive (SP), and multiple positive (MP). Comparative analyses of clinicopathological factors and survival using combinations of biomarkers were performed. Among the 698 GEA patients analyzed, 251 (36.0%) were classified as TN, 334 (47.9%) as SP, and 113 (16.1%) as MP. The MP group showed a significant association with tumors located in the esophagus (p < .001), well to moderate differentiation (p < .001), and the absence of signet ring cells (p < .001). In the survival analysis, MP group had a significantly longer overall survival (OS) compared to the other groups (MP vs. TN, p < .001 and MP vs. SP, p < .001). Multivariate Cox regression analysis revealed that MP serves as an independent positive prognostic indicator for OS (hazard ratio = 0.63, p < .01). Our findings indicate that MP biomarkers are associated with a favorable prognosis in metastatic GEA. These results are reflective of clinical practice and offer valuable insights into how therapeutics and future biomarkers could influence therapy/prognosis.

SMARCA4 Mutations in Gastroesophageal Adenocarcinoma: An Observational Study via a Next-Generation Sequencing Panel.

BACKGROUND: The clinical impact of SMARCA4 mutations (SMARCA4ms) in gastroesophageal adenocarcinoma (GEA) remains underexplored. This study aimed to examine the association of SMARCA4ms with clinical outcomes and co-occurrence with other gene mutations identified through a next-generation sequencing (NGS) panel in GEA patients. METHODS: A total of 256 patients with metastatic or recurrent GEA who underwent NGS panel profiling at the MD Anderson Cancer Center between 2016 and 2022 were included. Comparative analyses were performed to assess clinical outcomes related to SMARCA4ms. The frequency and types of SMARCA4ms and their co-occurrence with other gene mutations were also examined. RESULTS: SMARCA4ms were identified in 19 patients (7.4%). These SMARCA4ms were significantly associated with non-signet ring cell subtype (p = 0.044) and PD-L1 positive expression (p = 0.046). No difference in survival between the SMARCA4m and SMARCA4-normal group was observed (p = 0.84). There were significant associations between SMARCA4ms and FANCA, IGF1R, KRAS, FANCL, and PTEN alterations. Notably, 15 of the 19 SMARCA4m cases involved SNV missense mutations, with frequent co-occurrences noted with TP53, KRAS, ARID1A, and ERBB2 mutations. CONCLUSIONS: These results serve as the first comprehensive examination of the relationship between SMARCA4ms and clinical outcomes in GEA.

Activating argumentation schema to write argumentatively and tactfully.

To argue tactfully is a goal in argumentative writing, which entails balanced argumentation schema. Although computer-supported collaborative learning (CSCL) has been widely acknowledged as language learning mediation, especially in writing, few studies investigate its effectiveness in activating the balanced argumentation schema. This study explores the effectiveness of QQ group discussion, a kind of CSCL mediation most popular in China, in argumentative writing by means of quasi-experiment and interview. Fifty-six second-year college students in an English Department participated in this study. The experimental group were asked to have a pre-writing QQ group discussion on a disputable topic while the control group had an in-class face-to-face discussion (a regular teaching method for English majors). Content analysis of the essays was made to investigate the use of Counterargument elements, Qualifier and Concession. The results show that the two groups had no difference in the use of Counterargument-claim and Rebuttal. However, the experimental group surpassed the control group in Counterargument-data, Concession and Qualifier, which signifies more argumentativeness and tactfulness. In the delayed post-test this group still performed better. The interview transcriptions were coded and analyzed by inductive content analysis with the functions of QQ discussion as the themes. The result not only supported that of the experiment, but also revealed why and how QQ mediation could help activate the balanced argumentation schema. It is suggested that CSCL mediation should be promoted in argumentative writing instruction so that the students could write argumentatively and tactfully.

Exploratory pilot study to characterize the immune landscapes of malignant pleural effusions and their corresponding primary tumors from patients with breast carcinoma and lung adenocarcinoma.

INTRODUCTION: Malignant pleural effusion (MPE) is a frequent complication of advanced malignancies. In this pilot study, we characterized the immune landscapes of MPEs, compared them to their primary tumor (PT) samples from breast carcinoma (BC) and lung adenocarcinoma (LADC), and tested the utility of multiplexed image technology in cytological samples. MATERIALS AND METHODS: We evaluated the immune contexture of 6 BC and 5 LADC MPEs and their PTs using 3 multiplex immunofluorescence panels. We explored the associations between sample characteristics and pleural effusion-free survival. RESULTS: No MPE samples had positive programmed death-ligand 1 expression in malignant cells, although 3 of 11 PTs has positive programmed death-ligand 1 expression (more than 1% expression in malignant cells). Overall, in LADC samples, cluster of differentiation 3 (CD3)+ T cells and CD3+CD8+ cytotoxic T cells predominated (median percentages for MPEs versus PTs: 45.6% versus 40.7% and 4.7% versus 6.6%, respectively) compared with BC. CD68+ macrophages predominated in the BC samples (medians for MPEs 61.2% versus PTs for 57.1%) but not in the LADC samples. Generally in PTs, CD3+CD8+ forkhead box P3+ T cells and the median distances from the malignant cells to CD3+CD8+Ki67+ and CD3+ programmed cell death protein 1 + T cells correlated to earlier MPE after PT diagnosis. CONCLUSIONS: The immune cell phenotypes in the MPEs and PTs were similar within each cancer type but different between BC versus LADC. An MPE analysis can potentially be used as a substitute for a PT analysis, but an expanded study of this topic is essential.

The Utility of Fine Needle Aspiration (FNA) Biopsy in the Diagnosis of Mediastinal Lesions.

Fine needle aspiration is a minimally invasive, low-morbidity, and cost-efficient technique for the sampling of mediastinal lesions. Additionally, ancillary testing on FNA samples can be used for the refinement of diagnoses and for treatment-related purposes (flow cytometry, cytogenetics, immunohistochemistry, and molecular diagnostics). Mediastinal lesions, however, can show a variety of lineages and morphologic features, giving rise to diagnostic dilemmas. As a result, the differential diagnosis can vary widely and becomes especially challenging due to the smaller sample size on FNA and the variability in component sampling. For appropriate patient management and to determine the correct treatment strategies, accurate pathologic diagnoses are paramount. In this review, we present the cytomorphologic features together with the immunophenotypic findings of mediastinal lesions, with emphasis on the diagnostic challenges and pitfalls in FNA cytology samples, including smears and cell block sections.

Desmoplastic Small Round Cell Tumor Involving Serous Fluid: Cytologic Features and Diagnostic Pitfalls: A Series of 8 Cases.

OBJECTIVES: When desmoplastic small round cell tumor (DSRCT) is present in serous fluid, the cytomorphology can be diverse and can mimic metastatic carcinomas and thus present a diagnostic challenge. The aim of this study was to evaluate the cytomorphologic and immunocytochemical features of this rare tumor in serous effusion specimens. METHODS: Demographic, clinical, radiologic, and pathologic information from patients who had a DSRCT diagnosis on body fluid specimens was collected and cytologic slides were reviewed. RESULTS: Nine specimens were identified (5 pleural fluid and 4 ascitic fluid specimens) from 8 patients (5 male and 3 female). The mean patient age at diagnosis was 26 years. The most common symptoms were abdominal distension and pain, with 5 patients having abdominal masses. Other findings included peritoneal carcinomatosis, liver masses, ascites, and pleural nodules. The predominant cytomorphology was loose cellular clusters, followed by tight clusters of small cells with scant occasional vacuolated cytoplasm and a sphere-like pattern. CONCLUSIONS: Serous fluid may be the first available specimen to diagnose DSRCT. In young patients with no history of malignancy and radiologic finding of peritoneal implants, DSRCT should be considered a possibility in the differential diagnosis, and sensitive markers should be used for accurate diagnosis.

Pulmonary Sclerosing Pneumocytomas Mimicking Lung Cancer.

Pulmonary sclerosing pneumocytomas are benign tumors. These tumors are often found incidentally and can be challenging to distinguish from lung malignancies. Here, we describe the case of a 31-year-old woman who presented with an incidental finding of a lung nodule in the lingula. She was asymptomatic and had no history of cancer. Positron emission tomography showed [18F] fluorodeoxyglucose (FDG) uptake in the nodule but no FDG-avid mediastinal lymphadenopathy. In view of these findings, a bronchoscopy was performed, and biopsy samples were taken. The final pathological diagnosis revealed a sclerosing pneumocytoma.

The utility of claudin-4 versus MOC-31 and Ber-EP4 in the diagnosis of metastatic carcinoma in cytology specimens.

BACKGROUND: Claudin-4 is a sensitive and specific marker for carcinoma in effusion cytology. The authors examined the diagnostic use of claudin-4 versus MOC-31 and Ber-EP4 by comparing their sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) in differentiating carcinoma from mesothelioma and benign/mesothelial hyperplasia in effusion specimens. METHODS: This retrospective study comprised a cohort of 229 cytology specimens, including 211 effusion fluid and 18 fine-needle aspiration specimens. Cytologic categories included 134 carcinoma, 28 mesothelioma, 46 indefinite (suspicious and atypical), and 21 benign. Cell block sections were stained for claudin-4 and compared with those previously stained for MOC-31 and Ber-EP4. Indefinite cases were further reclassified based on clinical and pathologic findings into benign (26 cases), mesothelioma (11 cases), and carcinoma (nine cases). RESULTS: None of the mesotheliomas (0/39) or benign effusions (0/47) were positive for claudin-4, whereas 134 of the 143 carcinoma specimens were positive. Compared to MOC-31 and Ber-EP4, claudin-4 had the highest specificity and PPV (100% for each), followed by Ber-EP4. Claudin-4 showed high sensitivity (93.7%), albeit lower than MOC-31. MOC-31 had the lowest specificity and PPV but the highest sensitivity and NPV. Ber-EP4 had the lowest sensitivity (91.6%). CONCLUSIONS: Claudin-4 can be used as a single marker for carcinoma with high sensitivity and superior specificity compared with MOC-31 and Ber-EP4. Mesothelial lineage can be ruled out when claudin-4 is positive. In equivocal cytology samples with few scattered cells of interest, a panel of claudin-4 and Ber-EP4 results in the highest combined sensitivity and specificity.

Specimen Considerations in Molecular Oncology Testing.

Proper treatment of the patient with cancer depends on an accurate diagnosis of the tumor and is further directed by prognostic and more recently therapeutic molecular signatures in the era of precision medicine. Molecular oncology testing provides diagnostic, prognostic, and therapeutic information derived from the tumor genome. The aim of this review is to provide valuable information to laboratories for choosing optimal clinical specimens for molecular oncology testing by evaluating the strengths and weaknesses of different sample types from the procurement, processing, and pre-analytic selection matching to different test platforms.

A pilot study: Comparison of TRPS1 and GATA3 immunoperoxidase staining using cytologic smears in entities reportedly positive for GATA3.

BACKGROUND: Metastatic breast carcinoma (mBC) is frequently encountered and may be challenging to diagnose as the tumor cells can morphologically resemble carcinomas of other primary origins. An additional challenge is that direct smears are often the only sample type available for immunostaining studies in cytology. Trichorhinophalangeal syndrome GATA-binding type 1 1 (TRPS1) is a highly sensitive marker for BC compared to the commonly used marker GATA3, especially in triple-negative BC (TNBC), in histologic samples. However, its sensitivity and specificity in mBC and other GATA3-positive tumors have not been studied. METHODS: The authors identified the following cytology cases: 37 GATA3-positive mBC cases and 19 available cases that were deemed mBC but were GATA3-negative during the original case workup and five cases of each of eight epithelioid entities known to have high rates of GATA3 positivity and commonly seen in cytology practice. Immunostainings of TRPS1 and GATA3 were performed on the chosen smears following standard protocols. RESULTS: TRPS1 was positive in all 37 GATA3-positive mBC cases and in 18 of the 19 GATA3-negative mBC cases. TRPS1 was negative in all five of the seven frequently GATA3-positive epithelioid entities, with the exception of salivary duct carcinomas where GATA3 was positive in a rate ranging 60%-100% among them. CONCLUSIONS: TRPS1 is as sensitive as GATA3 in GATA3-positive mBC and is more sensitive than GATA3 in TNBC. TRPS1 is negative in most GATA3-positive nonbreast tumors. Thus, the combination of TRPS1 and GATA3 could be used to differentiate breast primary from others in most situations.

TRPS1, GATA3, and SOX10 expression in triple-negative breast carcinoma.

A diagnostic dilemma can be encountered when primary triple-negative breast carcinoma (TNBC) without an in situ component or metastatic TNBCs lose the currently used organ-specific marker such as GATA3, raising concerns about metastatic carcinoma from other sites. In the current study, we compared the newly identified breast marker TRPS1 with currently used breast markers GATA3 and SOX10 in whole-tissue sections from 315 cases of various subtypes of TNBC. TRPS1 was highly expressed in 100% of triple-negative primary and metastatic invasive lobular carcinomas, 99% of triple-negative primary and metastatic invasive breast carcinoma of no special type (IBC-NST), and 95% of metaplastic breast carcinomas. In contrast, GATA3 and SOX10 were expressed in 94% and 0% of invasive lobular carcinomas, 63% and 74% of IBC-NST, and 50% and 49% of metaplastic breast carcinomas, respectively. For special-type TNBCs, both TRPS1 and GATA3 were negative in acinic cell carcinomas, most cribriform adenoid cystic carcinomas, and neuroendocrine carcinomas, but positive in secretory carcinomas. Triple-negative apocrine carcinoma was the only subtype of TNBC with positive GATA3 but negative TRPS1. These data indicate that TRPS1 is a highly sensitive marker for TNBCs with positivity not only in GATA3/SOX10-positive TNBCs but also in almost all GATA3/SOX10-negative TNBCs.

Primary Pancreatic Lymphoma Evaluated by Fine-Needle Aspiration.

OBJECTIVES: Primary pancreatic lymphoma (PPL) is rare, mimicking pancreatic ductal adenocarcinoma (PDAC) clinically and radiologically. The aim of this study is to evaluate the clinical, radiologic, and pathological characteristics of PPL diagnosed by fine-needle aspiration (FNA) in our institution. METHODS: Patient clinical, radiologic, and pathological information was collected from the electronic health record system. RESULTS: In total, 11 of 4,353 pancreatic FNAs met the criteria. The most common clinical symptom was jaundice, followed by abdominal pain, weight loss, and diarrhea. Abnormal laboratory findings included elevated alkaline phosphatase, total bilirubin, lactate dehydrogenase, and cancer antigen 19-9. Abnormal radiologic findings included pancreatic mass, biliary dilatation, vessel encasement, and common bile duct encasement and thickening. Five patients underwent more than 1 tissue sampling procedure before the final diagnosis of lymphoma. Final pathologic diagnosis included 7 large B-cell lymphomas and 4 follicular lymphomas. Flow cytometric analysis was performed on 9 specimens, and all demonstrated an aberrant monoclonal B-cell population. CONCLUSIONS: PPL mimics PDAC clinically and radiologically and could be a challenge for pathologic diagnosis if lymphoma is not included in the differential diagnosis during immediate evaluation. If lymphoma is suspected during immediate evaluation, PPL could be reliably diagnosed by FNA with the aid of ancillary studies.

Expression of TRPS1 in phyllodes tumor and sarcoma of the breast.

When a sarcomatous neoplasm is identified in the breast, distinguishing metaplastic carcinoma, malignant phyllodes tumor (MPT), and primary sarcoma is a diagnostic challenge, especially on small biopsies, as all these tumors may have overlapping morphological features, thoroughly grossing with histological examination and immunohistochemical staining being the standard approach to aid in classifying these lesions. Recently, we identified a highly sensitive and specific breast carcinoma marker TRPS1 with high expression in metaplastic breast carcinoma. In the current study, we tested TRPS1 in MPTs and primary sarcoma of the breast. We found TRPS1 was highly expressed (95%) within spindle cell, chondro-osseous, and/or liposarcomatous components of MPTs, in all breast primary chondrosarcomas and extraskeletal osteosarcomas, but not in other sarcomas of the breast. In extramammary sarcomas, TRPS1 was expressed in 28% of conventional chondrosarcomas and 56% of osteosarcomas of bone, but rarely in undifferentiated pleomorphic sarcomas (UPSs), liposarcomas, and angiosarcomas. In summary, MPTs may share similar genetic background with metaplastic carcinoma exhibiting TRPS1 expression, and TRPS1 may play a role in chondro-osseous differentiation because of its expression in chondro-osseous sarcomas from both breast and extramammary sites. Our findings suggest TRPS1 may be clinically useful in distinguishing MPT and metaplastic carcinoma from primary breast sarcoma except for tumors with chondro-osseous differentiation.

Detection of non-haematolymphoid malignancies in bronchoalveolar lavages-A cancer centre's 10 year experience.

INTRODUCTION: Fibreoptic bronchoscopy with bronchoalveolar lavage (FOB-BAL) is often performed in immunocompromised and cancer patients to investigate possible infectious and non-infectious causes of clinical and radiological respiratory abnormalities. Knowledge of the incidence and distribution of non-haematolymphoid malignancies (NHLM) detected by FOB-BAL in this population is limited. METHOD: Our pathology electronic database was searched from July 1, 2008 to June 30, 2018 for BAL specimens with diagnoses of "malignant" and a review of the pathology report and electronic medical record was performed. Statistical analyses were performed to determine the incidence, distribution of NHLM, and demographics of patients in these BALs. RESULTS: A total of 209 (1.92%) out of 11 035 BAL cases were reported in the "malignant" category. After exclusion of 22 cases with haematolymphoid malignancies, 187 cases were included in this study. The average patient age was 58 years (ranging from 9 to 83 years). The most common NHLM identified were from lung/thoracic primaries (n = 103; 55.1%) with adenocarcinoma being the most common type of lung primary (n = 91; 88%). Other tumours detected included carcinomas from breast (n = 34; 18.2%), gastrointestinal tract (n = 17; 9.1%), genitourinary tract (n = 13; 7%), Müllerian origin (n = 8; 4.3%), and head and neck (n = 6; 3.2%). Rarer NHLM encompassed 3.2% of BALs (n = 6). CONCLUSION: FOB-BAL is a useful tool for evaluating various pulmonary abnormalities in our cancer institute's patient population and a valuable method for detecting NHLM, which is critical to guide appropriate subsequent therapies.

Clinical and cytopathological features of suspected thyroglossal duct cysts and neoplasms arising from them: A large series from a referral cancer center.

BACKGROUND: Thyroglossal duct cysts (TGDCs) are the most common congenital midline cystic lesions in the neck, and they are often evaluated by fine-needle aspiration. Recognizing the cytomorphologic features of TGDCs and their mimics is important for clinical management. METHODS: This study examined the clinical, radiological, and cytopathological features of 86 ultrasonography-guided fine-needle aspiration (US-FNA) specimens from clinically suspected TGDCs or malignancies arising from TGDCs and correlated the findings with surgical follow-up and/or imaging studies. RESULTS: According to ultrasound examinations of 66 lesions, 17 (25.8%) were cystic, 8 (12.1%) were cystic with septations, 21 (31.8%) were cystic with solid nodules, and 20 (30.3%) were solid or cystic with internal debris. Cytopathologically, 81 lesions (94%) were categorized as benign, 2 (2%) were categorized as atypical, and 3 (3%) were categorized as malignant. In benign lesions, proteinaceous material (63%), histiocytes (63%), colloid (37%), squamous cells (35%), columnar cells (32%), follicular cells (15%), inflammatory cells (9%), and multinucleated giant cells (9%) were noted. Diagnoses in the benign category included TGDC in 64 patients (75%), TGDC or mimics (colloid nodule/epidermoid cyst) in 14 patients (17%), a colloid nodule in 1 patient, and thyroiditis in 1 patient. Surgical resection, performed in 23 patients, confirmed TGDCs in 12, benign mimics in 7, and carcinoma in 4. CONCLUSIONS: Cytopathological features, in conjunction with imaging, allowed a definite diagnosis of TGDC in most patients (75%). The presence of mature squamous cells, thyroid follicular cells, with or without colloid and/or lymphocytes alone allowed a differential diagnosis of TGDC and its mimics in 17%. US-FNA findings could not distinguish primary carcinomas arising from TGDCs from metastatic tumors.

Adequacy evaluation and use of pancreatic adenocarcinoma specimens for next-generation sequencing acquired by endoscopic ultrasound-guided FNA and FNB.

BACKGROUND: Endoscopic ultrasound-guided tissue acquisition (EUS-TA), especially endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA), is the mainstay of tissue acquisition for the diagnosis of pancreatic ductal adenocarcinoma (PDAC). Recently, endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) using flexible biopsy needles has been used for patients with PDAC in an effort to increase diagnostic yields and biomarker testing. However, the role of EUS-TA in biomarker testing for personalized therapy or precise chemotherapy for PDAC is not well established. METHODS: PDAC cases with specimens acquired through concurrent EUS-FNA and EUS-FNB were identified retrospectively. Smears were prepared from EUS-FNA sampling, and cell blocks (CBs) were prepared from EUS-FNB sampling. Rapid onsite evaluation was conducted for all cases for diagnostic adequacy. The adequacy for biomarker testing, including next-generation sequencing (NGS) and immunohistochemistry (IHC) assays, was evaluated, and cases with smears and CBs adequate for NGS were processed for targeted NGS. RESULTS: There were 26 PDAC cases concurrently sampled by EUS-FNA and EUS-FNB. EUS-FNA smears for all 26 cases and EUS-FNB CBs for 20 cases (77%) were diagnostic for PDAC. Twenty-one smears (81%) and 11 CBs (42%) were adequate for NGS. Nine cases with both smears and CBs adequate for NGS underwent NGS, which identified clinically significant gene mutation variants, including KRAS, TP53, and SMAD4 mutations. CONCLUSIONS: Both EUS-FNA and EUS-FNB can provide optimal material for targeted NGS for PDACs. In PDAC cases subjected to concurrent EUS-FNA and EUS-FNB, EUS-FNA specimens had greater diagnostic yields and more adequate material for NGS than EUS-FNB specimens, whereas EUS-FNB was more suitable for IHC-based biomarker testing.

Imaging of Cervical Lymph Nodes in Thyroid Cancer: Ultrasound and Computed Tomography.

Sonographic evaluation of cervical lymph nodes in patients with thyroid malignancy is important both for preoperative staging and for post-treatment surveillance, and contrast-enhanced computed tomography plays a complementary role. Knowledge of anatomy and surgical approaches, combined with an understanding of the various imaging features that distinguish malignant from benign lymph nodes, allows for accurate staging, thereby enabling complete surgical initial resection.

Patient-derived cell lines and orthotopic mouse model of peritoneal carcinomatosis recapitulate molecular and phenotypic features of human gastric adenocarcinoma.

BACKGROUND: Gastric adenocarcinoma with peritoneal carcinomatosis (PC) is therapy resistant and leads to poor survival. To study PC in depth, there is an urgent need to develop representative PC-derived cell lines and metastatic models to study molecular mechanisms of PC and for preclinical screening of new therapies. METHODS: PC cell lines were developed from patient-derived PC cells. The tumorigenicity and metastatic potential were investigated by subcutaneously (PDXs) and orthotopically. Karyotyping, whole-exome sequencing, RNA-sequencing, and functional studies were performed to molecularly define the cell lines and compare genomic and phenotypic features of PDX and donor PC cells. RESULTS: We established three PC cell lines (GA0518, GA0804, and GA0825) and characterized them in vitro. The doubling times were 22, 39, and 37 h for GA0518, GA0804, and GA0825, respectively. Expression of cancer stem cell markers (CD44, ALDH1, CD133 and YAP1) and activation of oncogenes varied among the cell lines. All three PC cell lines formed PDXs. Interestingly, all three PC cell lines formed tumors in the patient derived orthotopic (PDO) model and GA0518 cell line consistently produced PC in mice. Moreover, PDXs recapitulated transcriptomic and phenotypic features of the donor PC cells. Finally, these cell lines were suitable for preclinical testing of chemotherapy and target agents in vitro and in vivo. CONCLUSION: We successfully established three patient-derived PC cell lines and an improved PDO model with high incidence of PC associated with malignant ascites. Thus, these cell lines and metastatic PDO model represent excellent resources for exploring metastatic mechanisms of PC in depth and for target drug screening and validation by interrogating GAC for translational studies.