Lung Metastatic Sites Research Articles

METTL14-mediated m6A mRNA modification of G6PD promotes lung adenocarcinoma

METTL14 functions as an RNA methyltransferase involved in m6A modification, influencing mRNA biogenesis, decay, and translation processes. However, the specific mechanism by which METTL14 regulates glucose-6-phosphate dehydrogenase (G6PD) to promote the progression of lung adenocarcinoma (LUAD) is not well understood. Quantitative measurement and immunohistochemistry (IHC) analysis have demonstrated higher levels of m6A in LUAD tissues compared to adjacent normal tissues. Additionally, the expression of METTL14 was significantly increased in LUAD tissues. In LUAD cell lines, both METTL14 and m6A levels were elevated compared to normal human lung epithelial cells. Knockdown of METTL14 markedly reduced LUAD cell proliferation, migration, and invasion. Conversely, overexpression of METTL14, but not the mutant form, significantly enhanced these cellular processes in LUAD. In vivo studies using nude mice with subcutaneously transplanted LUAD cells demonstrated that stable METTL14 knockdown led to notably reduced tumor volume and weight, along with fewer Ki67-positive cells and lung metastatic sites. Importantly, METTL14 knockdown reduced glycolytic activity in LUAD cells. Through a combination of RNA sequencing and MeRIP-sequencing, we identified numerous altered genes and confirmed that IGF2BP2 enhances G6PD mRNA stability after METTL14-mediated m6A modification, thereby promoting tumor growth and metastasis. Moreover, LUAD patients with higher levels of G6PD had poorer overall survival (OS). In conclusion, our study indicates that METTL14 upregulates G6PD expression post-transcriptionally through an m6A-IGF2BP2-dependent mechanism, thereby stabilizing G6PD mRNA. These findings propose potential diagnostic biomarkers and effective targets for anti-metabolism therapy in LUAD.

NQO1 Triggers Neutrophil Recruitment and NET formation to Drive Lung Metastasis of Invasive Breast Cancer.

Metastasis to the lungs is a leading cause of death for breast cancer patients. Therefore, effective therapies are urgently needed to prevent and treat breast cancer lung metastasis In this study, we uncovered a mechanism by which NAD(P)H:quinone oxidoreductase 1 (NQO1) orchestrates lung metastasis. NQO1 stabilized and upregulated peptidyl-prolyl cis-trans isomerase A (PPIA), a chaperone that regulates protein conformation and activity, by preventing its oxidation at a critical cysteine residue C161. PPIA subsequently activated CD147, a membrane protein that facilitates cell invasion. Moreover, NQO1-induced secretion of PPIA modulated the immune landscape of both primary and lung metastatic sites. Secreted PPIA engaged CD147 on neutrophils and triggered the release of neutrophil extracellular traps (NET) and neutrophil elastase, which enhanced tumor progression, invasiveness and lung colonization. Pharmacological targeting of PPIA effectively inhibited NQO1-mediated breast cancer lung metastasis. These findings reveal a previously unrecognized NQO1-PPIA-CD147-NET axis that drives breast cancer lung metastasis. Inhibiting this axis is a potential therapeutic strategy to limit lung metastasis in breast cancer patients.

Identification and Characterization of Metastasis-Initiating Cells in ESCC in a Multi-Timepoint Pulmonary Metastasis Mouse Model.

Metastasis is the biggest obstacle to esophageal squamous cell carcinoma (ESCC) treatment. Single-cell RNA sequencing analyses are applied to investigate lung metastatic ESCC cells isolated from pulmonary metastasis mouse model at multiple timepoints to characterize early metastatic microenvironment. A small population of parental KYSE30 cell line (Cluster S) resembling metastasis-initiating cells (MICs) is identified because they survive and colonize at lung metastatic sites. Differential expression profile comparisons between Cluster S and other subpopulations identified a panel of 7 metastasis-initiating signature genes (MIS), including CD44 and TACSTD2, to represent MICs in ESCC. Functional studies demonstrated MICs (CD44high) exhibited significantly enhanced cell survival (resistances to oxidative stress and apoptosis), migration, invasion, stemness, and in vivo lung metastasis capabilities, while bioinformatics analyses revealed enhanced organ development, stress responses, and neuron development, potentially remodel early metastasis microenvironment. Meanwhile, early metastasizing cells demonstrate quasi-epithelial-mesenchymal phenotype to support both invasion and anchorage. Multiplex immunohistochemistry (mIHC) staining of 4 MISs (CD44, S100A14, RHOD, and TACSTD2) in ESCC clinical samples demonstrated differential MIS expression scores (dMISs) predict lymph node metastasis, overall survival, and risk of carcinothrombosis.

Correlation between metastatic site and immunotherapy efficacy in patients with advanced dMMR/MSI colorectal cancer: Real-World Italian multicentric retrospective study (Colon-MSI).

e15544 Background: Immune checkpoint inhibitors (ICIs) are the gold standard therapy in metastatic colorectal cancer (mCRC) patients (pts) with microsatellite instability (MSI). The Colon-MSI study aimed to describe a cohort of MSI mCRC pts treated with ICIs before Italian pembrolizumab approval and to evaluate the efficacy, safety, and possible predictive factors of response in a real-world setting. Methods: We retrospectively collected data of pts with MSI mCRC treated with ICIs before June 30, 2023, in 16 Italian Cancer Centers. The OS was calculated from the diagnosis of metastatic disease, and the PFS from the beginning of ICIs. We explored the correlation between clinicopathological factors, survival outcomes, and treatment response. Results: Between January 2021 and June 2023, we reported 83 consecutive pts with data available. Among all, the median age was 61 years (23-86), 42 (51%) were female, and 45 (54%) had a ECOG PS 0; 35 (42%) pts were at stage IV at diagnosis, and 61 (74%) had right colon tumor site. The most common metastatic sites were liver (35%), lymph nodes (43%), peritoneum (31%), and lung (15%); 48 (58%) pts had a single metastatic site. 33 (39%) pts had a mucinous adenocarcinoma, 32 (39%) BRAF mutated, 32 (39%) RAS mutated, and 26% presented a Lynch syndrome. The majority of pts (69%) were pre-treated, and 26 pts (31%) received ICIs in first line. Nivolumab alone or plus Ipilimumab, and Pembrolizumab, were administered in 23 (28%), 3 (4%), and 57 (68%) pts, respectively. The median follow-up was 23 (1-65) months (m) and the median duration of treatment was 23 m (0-65) with 27 pts still ongoing. Treatment-related severe toxicities (G3 or G4) were observed only in 5.6% of pts. The median OS and PFS were not reached; the mean OS was 45.6 m (IC 95% 39.6-51.6) and the mean PFS was 38.8 m (IC 95% 32.5-45.1). Complete response (CR) was observed in 20 pts (24%), partial response (PR) in 28 (34%), stable disease (SD) in 19 (23%) and progression disease (PD) in 16 (19%). Overall response (ORR) was observed in 48 pts (57.8%; 95 %IC 0.31- 0.53), and disease control rate in 67 pts (80.7%; 95% IC 0.11– 0.29). Lung metastatic site was associated with poorer outcome in terms of OS (p = 0.001, HR 3.88 IC 95% 1.7-8.9), PFS (p = 0.045 HR = 2.31 IC95% 1-5.2), and ORR (p = 0.015 OR = 6.19 IC95% 1.4-26.9). Significantly worse PFS was also observed in pts with liver metastasis (p = 0.009 HR = 2.5 IC 95% 1.3-4.9). Conclusions: Our data confirm that ICIs are effective and well-tolerated treatment in MSI mCRC pts, with long-term clinical outcomes reported. These results suggest an unfavorable correlation between lung and liver metastasis and the ICI response. Further biomolecular analysis will be provided in the future.

The incorporation of acetylated LAP-TGF-β1 proteins into exosomes promotes TNBC cell dissemination in lung micro-metastasis

Triple-negative breast cancer (TNBC) stands as the breast cancer subtype with the highest recurrence and mortality rates, with the lungs being the common site of metastasis. The pulmonary microenvironment plays a pivotal role in the colonization of disseminated tumor cells. Herein, this study highlights the crucial role of exosomal LAP-TGF-β1, the principal form of exosomal TGF-β1, in reshaping the pulmonary vascular niche, thereby facilitating TNBC lung metastasis. Although various strategies have been developed to block TGF-β signaling and have advanced clinically, their significant side effects have limited their therapeutic application. This study demonstrates that in lung metastatic sites, LAP-TGF-β1 within exosomes can remarkably reconfigure the pulmonary vascular niche at lower doses, bolstering the extravasation and colonization of TNBC cells in the lungs. Mechanistically, under the aegis of the acetyltransferase TIP60, a non-canonical KFERQ-like sequence in LAP-TGF-β1 undergoes acetylation at the K304 site, promoting its interaction with HSP90A and subsequent transport into exosomes. Concurrent inhibition of both HSP90A and TIP60 significantly diminishes the exosomal burden of LAP-TGF-β1, presenting a promising therapeutic avenue for TNBC lung metastasis. This study not only offers fresh insights into the molecular underpinnings of TNBC lung metastasis but also lays a foundation for innovative therapeutic strategies.

Comparison of primary and metastatic site-related PD-L1 expression in predicting ORR in patients with advanced NSCLC who received ICB-based therapy.

Whether the value of PD-L1 expression from metastatic sites to predict the efficacy of immune checkpoint blockade (ICB)-based treatment is equivalent to that from a primary tumor is uncertain. This study aimed to compare the utility of PD-L1 TPS from a primary lung tumor and metastatic sites to predict the overall response rate (ORR) of first-line ICB-based treatment. This study included 249 patients with advanced non-small cell lung cancer (NSCLC) who received first-line ICB-based treatment. All subjects underwent PD-L1 testing prior to ICB-based treatment and were divided into two cohorts corresponding to the different biopsy sites: lung primary site-sampled cohort (PT cohort, n = 167) and metastatic site-sampled cohort (MT cohort, n = 82). There was no statistical significance in PD-L1 TPS distribution between the two cohorts (p = 0.742). PD-L1 TPS ≥50% was also related to high ORR compared with PD-L1 < 50% in the PT cohort (34.3% vs. 14.1%, p = 0.004). In contrast, ICB-based therapy could bring comparable ORR (35.1% vs. 33.3%, p = 0.871) in the MT cohort regardless of PD-L1 TPS status (≥50%, or <50%). As supported, when the cutoff value of TPS was selected as 50%, it was suggested that PT-related PD-L1 was the independent predictor of ORR (OR 2.870, 95% CI: 1.231-6.694, p = 0.015) rather than MT-related PD-L1 (OR 0.689, 95% CI: 0.236-2.013, p = 0.495). Furthermore, ROC proved that PT-related PD-L1 expression manifested a better AUC of 0.621 (p = 0.026) than that of MT-related PD-L1 (AUC = 0.565, p = 0.362). Compared with PT-related PD-L1 expression, MT-related PD-L1 expression showed limited value in predicting ORR in patients with advanced NSCLC receiving ICB-based therapy. It was concluded that even patients with low MT-related PD-L1 expression could benefit from ICB-based therapy.

A decellularized lung extracellular matrix/chondroitin sulfate/gelatin/chitosan-based 3D culture system shapes breast cancer lung metastasis

Distal metastasis of breast cancer is a primary cause of death, and the lung is a common metastatic target of breast cancer. However, the role of the lung niche in promoting breast cancer progression is not well understood. Engineered three-dimensional (3D) in vitro models capable of bridging this knowledge gap can be specifically designed to mimic crucial characteristics of the lung niche in a more physiologically relevant context than conventional two-dimensional systems. In this study, two 3D culture systems were developed to mimic the late stage of breast cancer progression at a lung metastatic site. These 3D models were created based on a novel decellularized lung extracellular matrix/chondroitin sulfate/gelatin/chitosan composite material and on a porcine decellularized lung matrix (PDLM), with the former tailored with comparable properties (stiffness, pore size, biochemical composition, and microstructure) to that of the in vivo lung matrix. The different microstructure and stiffness of the two types of scaffolds yielded diverse presentations of MCF-7 cells in terms of cell distribution, cell morphology, and migration. Cells showed better extensions with apparent pseudopods and more homogeneous and reduced migration activity on the composite scaffold compared to those on the PDLM scaffold. Furthermore, alveolar-like structures with superior porous connectivity in the composite scaffold remarkably promoted aggressive cell proliferation and viability. In conclusion, a novel lung matrix-mimetic 3D in vitro breast cancer lung metastasis model was developed to clarify the underlying correlativity between lung ECM and breast cancer cells after lung colonization. A better understanding of the effects of biochemical and biophysical environments of the lung matrix on cell behaviors can help elucidate the potential mechanisms of breast cancer progression and further improve target discovery of therapeutic strategies.

Prediction of Disease Progression to Upfront Pembrolizumab Monotherapy in Advanced Non-Small-Cell Lung Cancer with High PD-L1 Expression Using Baseline CT Disease Quantification and Smoking Pack Years.

Health Canada approved pembrolizumab in the first-line setting for advanced non-small-cell lung cancer with PD-L1 ≥ 50% and no EGFR/ALK aberration. The keynote 024 trial showed 55% of such patients progress with pembrolizumab monotherapy. We propose that the combination of baseline CT and clinical factors can help identify those patients who may progress. In 138 eligible patients from our institution, we retrospectively collected their baseline variables, including baseline CT findings (primary lung tumor size and metastatic site), smoking pack years, performance status, tumor pathology, and demographics. The treatment response was assessed via RECIST 1.1 using the baseline and first follow-up CT. Associations between the baseline variables and progressive disease (PD) were tested by logistic regression analyses. The results showed 46/138 patients had PD. The baseline CT "number of involved organs" by metastasis and smoking pack years were independently associated with PD (p < 0.05), and the ROC analysis showed a good performance of the model that integrated these variables in predicting PD (AUC: 0.79). This pilot study suggests that the combination of baseline CT disease and smoking PY can identify who may progress on pembrolizumab monotherapy and can potentially facilitate decision-making for the optimal first-line treatment in the high PD-L1 cohort.

Dual Immune Checkpoint Blockade and Hypofractionated Radiation in Recurrent/Metastatic Squamous Cell Carcinomas of the Head and Neck Previously Treated with Immune Checkpoint Inhibitors

<h3>Purpose/Objective(s)</h3> This single arm open label phase II study sought to explore the safety and antitumor activity of combined antiPDL1 and CTLA4 blockade with hypofractionated radiation (XRT) in patients with recurrent/metastatic head and neck squamous cell carcinomas (RMHNSCC) who have previously been treated with an immune checkpoint inhibitor (ICI). <h3>Materials/Methods</h3> Patients with RMHNSCC who progressed on prior ICI, ECOG 0/1, a bone or lung metastatic site amenable to XRT and RECIST 1.1 measurable disease apart from the radiated site were eligible. Durvalumab 1500mg IV x 13 doses and tremelimumab 75mg IV x 4 doses were both administered every 4 weeks. Hypofractionated image-guided (HIGRT) or stereotactic (SBRT) XRT was given in 3 fractions every other day to a total dose of 24 Gy starting week 2. The primary endpoint was safety; secondary endpoints were RECIST 1.1 responses in non-radiated measurable lesions and overall survival (OS). Blood was obtained at baseline and at week 4 for flow cytometric peripheral T cell analysis. The accrual goal was 20 patients with the first 6 patients representing a safety run in cohort. This project was approved by our institutional IRB and registered at clinicaltrials.gov (NCT035225). <h3>Results</h3> Between August 2018 and November 2020, 6 patients were enrolled, followed by study closure by the sponsor due to funding. All patients were male, 4 white and 2 Asian, with a median age of 64 years (range 47-67), 4 had oropharynx, 1 oral cavity and 1 hypopharynx as primary sites, 5 were never smokers. All patients had progressed on ICI in the R/M setting (2 nivolumab, 2 pembrolizumab, 1 avelumab and 1 durvalumab). Five patients completed XRT: 4 to lung lesions and 1 to a superior mediastinal LN, no toxicities attributed to the radiation were observed. One patient was unable to receive XRT due to progression. Only 2 patients completed more than 4 treatment cycles (median 2.5, range 1-13 cycles). One dose limiting toxicity (recurrent Grade 2 diarrhea) was observed. Four grade 3 toxicities (neck pain due to tumor, shingles, dyspnea due to disease progression and fatigue) were observed in 3 patients, one of which was deemed treatment related (fatigue). Among 5 evaluable pts, we observed 1 complete response (CR), 3 stable disease (SD), 1 disease progression (PD). The patient with a CR showed an increase in PDL1+ and PD1+ T cells at 4 weeks, which was not observed in the 3 other evaluable patients with PD and SD. With one surviving patient in follow up for 14 months, median OS was 8 months (range 4-14). <h3>Conclusion</h3> In this small study population of previously ICI treated RMHNSCC, durvalumab, tremelimumab and XRT resulted in expected toxicities and limited efficacy. Increase in peripheral PDL1+ and PD1+ T cells may correlate with response and may merit further study.

Molecular alterations across sites of metastasis in patients with renal cell carcinoma (RCC).

287 Background: RCC has a distinct pattern of metastatic spread with common sites of metastasis including the lung, bone, and liver. Less common sites include the brain, adrenal gland, and pancreas. While the pattern of metastatic spread has prognostic significance, the biology driving tropism to specific organ sites has not been fully characterized. We utilized a multi-institutional real-world dataset to examine genomic alterations and transcriptional signatures across the spectrum of metastatic sites in patients with RCC. Methods: RCC tissue specimens derived from the kidney and distant metastatic sites were sequenced utilizing a commercially available Clinical Laboratory Improvement Amendments (CLIA)-certified assay by Caris Life Sciences. Whole exome and transcriptome sequencing was performed. Molecular subgroups were defined according to the IMmotion151 metastatic RCC subtypes, with subgroups determined by a weighted average of gene expression levels. Molecular analysis and PD-L1 expression (SP142) were described by metastasis site. Results: 657 RCC samples from 653 patients underwent molecular profiling. The median age was 62 years (range 14-90) and the majority were male (70.6%). The most common histology was clear cell RCC (n = 509, 77.5%), followed by papillary (n = 63, 9.6%), chromophobe (n = 30, 4.6%), medullary (n = 8, 1.2%), collecting duct (n = 6, 0.9%), and mixed (n = 41, 6.2%). Specimen source included the kidney (n = 340, 51.8%), lung (n = 75, 11.4%), bone (n = 45, 6.8%), lymph nodes (n = 34, 5.2%), liver (n = 28, 4.3%), endocrine glands (adrenal, pancreas, and thyroid; n = 23, 3.5%), brain/CNS (n = 16, 2.4%), and other metastatic sites (n = 96, 14.6%). Compared to kidney, several genes were mutated at higher rates for select metastatic sites, including PBRM1 (59.5% bone, 59.1% endocrine, and 45.9% lung vs 33.8% kidney, p&lt; 0.05) and KDM5C (27.8% endocrine, 29.2% lymph nodes, and 35.3% soft tissue vs 9.3% kidney, p&lt; 0.05). When evaluating metastatic specimens versus kidney specimens, bone metastases had a significantly higher proportion of tumors classified as ‘Angio/stromal’ (n = 19, 42.2%; vs n = 52, 15.4%; p&lt; 0.0001), while liver metastases had a higher proportion of the ‘complement/Ω-oxidation’ subgroup (n = 17, 60.7%; vs n = 48, 14.1%; p&lt; 0.0001). PD-L1 expression in metastatic sites (range 6.8%-21.7%, with exception of 0% in GI; p= 0.09 to 0.99) was not significantly different from the kidney (16.6%). Conclusions: In our contemporary real-world analysis, we demonstrate differential patterns of molecular alterations among sites of metastasis in RCC. Our observations elucidate the biology underlying heterogeneous disease outcomes associated with site of metastasis. Application of predictive signatures by site of metastasis may help inform personalized therapy strategies in advanced RCC. Further studies are warranted to validate our findings.

Systemic Injection of Oncolytic Vaccinia Virus Suppresses Primary Tumor Growth and Lung Metastasis in Metastatic Renal Cell Carcinoma by Remodeling Tumor Microenvironment.

Immune checkpoint inhibitors and tyrosine kinase inhibitors are the first-line treatment for metastatic renal cell carcinoma (mRCC), but their benefits are limited to specific patient subsets. Here, we aimed to evaluate the therapeutic efficacy of JX-594 (pexastimogene devacirepvec, Pexa-vec) monotherapy by systemic injection in comparison with sunitinib monotherapy in metastatic orthotopic RCC murine models. Two highly metastatic orthotopic RCC models were developed to compare the treatment efficacy in the International Metastatic RCC Database Consortium favorable-risk and intermediate- or poor-risk groups. JX-594 was systemically injected through the peritoneum, whereas sunitinib was orally administered. Post-treatment, tumor microenvironment (TME) remodeling was determined using immunofluorescence analysis. Systemic JX-594 monotherapy injection demonstrated therapeutic benefit in both early- and advanced-stage mRCC models. Sunitinib monotherapy significantly reduced the primary tumor burden and number of lung metastases in the early-stage, but not in the advanced-stage mRCC model. Systemic JX-594 delivery remodeled the primary TME and lung metastatic sites by increasing tumor-infiltrating CD4/8+ T cells and dendritic cells. Systemic JX-594 monotherapy demonstrated significantly better therapeutic outcomes compared with sunitinib monotherapy in both early- and advanced-stage mRCCs by converting cold tumors into hot tumors. Sunitinib monotherapy effectively suppressed primary tumor growth and lung metastasis in early-stage mRCC.

Natural exosome-like nanovesicles from edible tea flowers suppress metastatic breast cancer via ROS generation and microbiota modulation

Although several artificial nanotherapeutics have been approved for practical treatment of metastatic breast cancer, their inefficient therapeutic outcomes, serious adverse effects, and high cost of mass production remain crucial challenges. Herein, we developed an alternative strategy to specifically trigger apoptosis of breast tumors and inhibit their lung metastasis by using natural nanovehicles from tea flowers (TFENs). These nanovehicles had desirable particle sizes (131 nm), exosome-like morphology, and negative zeta potentials. Furthermore, TFENs were found to contain large amounts of polyphenols, flavonoids, functional proteins, and lipids. Cell experiments revealed that TFENs showed strong cytotoxicities against cancer cells due to the stimulation of reactive oxygen species (ROS) amplification. The increased intracellular ROS amounts could not only trigger mitochondrial damage, but also arrest cell cycle, resulting in the in vitro anti-proliferation, anti-migration, and anti-invasion activities against breast cancer cells. Further mice investigations demonstrated that TFENs after intravenous (i.v.) injection or oral administration could accumulate in breast tumors and lung metastatic sites, inhibit the growth and metastasis of breast cancer, and modulate gut microbiota. This study brings new insights to the green production of natural exosome-like nanoplatform for the inhibition of breast cancer and its lung metastasis via i.v. and oral routes.

A chemokine regulatory loop induces cholesterol synthesis in lung-colonizing triple-negative breast cancer cells to fuel metastatic growth

Triple-negative breast cancer (TNBC) has a high propensity for organ-specific metastasis. However, the underlying mechanisms are not well understood. Here we show that the primary TNBC tumor-derived C-X-C motif chemokines 1/2/8 (CXCL1/2/8) stimulate lung-resident fibroblasts to produce the C-C motif chemokines 2/7 (CCL2/7), which, in turn, activate cholesterol synthesis in lung-colonizing TNBC cells and induce angiogenesis at lung metastatic sites. Inhibiting cholesterol synthesis in lung-colonizing breast tumor cells by pulmonary administration of simvastatin-carrying HER3-targeting nanoparticles reduces angiogenesis and growth of lung metastases in a syngeneic TNBC mouse model. Our findings reveal a novel, chemokine-regulated mechanism for the cholesterol synthesis pathway and a critical role of metastatic site-specific cholesterol synthesis in the pulmonary tropism of TNBC metastasis. The study has implications for the unresolved epidemiological observation that use of cholesterol-lowering drugs has no effect on breast cancer incidence but can unexpectedly reduce breast cancer mortality, suggesting interventions of cholesterol synthesis in lung metastases as an effective treatment to improve survival in individuals with TNBC.

Abstract 2846: Stereotypic patterns and genomic correlates of organotropism in metastatic melanoma

Abstract Despite the major role that metastasis plays in the morbidity and mortality of melanoma, stereotyped patterns of metastasis and drivers of its organotropism in melanoma are still not well characterized, limited by a dearth of sequencing data in well-annotated clinical melanoma samples. To address these open questions, we performed an integrative analysis of clinical and genomic features from 243 patients with metastatic melanoma treated at Dana Farber Cancer Institute (DFCI). Tumor biopsies were sequenced with OncoPanel, a next-generation sequencing panel that identifies mutations in 331 cancer genes. Presence of site metastases was evaluated radiographically pre-treatment for each patient; sites include lymph node (64% of cohort), soft tissue (59%), lung (57%), liver (32%), brain (24%), bone (22%), mesentery (12%), adrenal gland (9%), spleen (7%), and other metastatic sites (13%). Metastases showed significant co-occurrences (e.g. bone and lung, OR 2.8, 95% CI = [2.3, 3.3], p &amp;lt; 0.01; adrenal and mesentery, OR 4.4, 95% CI = [3.8, 5.0], p &amp;lt; 0.01) and exclusions (lymph node and brain, OR 0.5, 95% CI = [0.2, 0.8], p = 0.02). We performed unsupervised hierarchical clustering of patients with cutaneous melanoma (n = 203) by metastatic site pattern using a Euclidean distance metric weighted to favor uncommon metastatic sites, yielding five stereotypic patterns of metastasis, characterized by: (1) co-occurrence of adrenal, mesenteric, and abdominal metastases (n=19); (2) liver metastases (n=33); (3) low metastatic burden (n=80); (4) co-occurrence of lung, brain, and mesentery metastases (n=42); and (5) co-occurrence of bone and lung metastases (n=29). Clustering is stable, with highly concordant cluster assignments in repeated subsampling of the data. Patients with cutaneous melanoma (n=203) exhibited both site-specific and pattern-specific genomic correlates of metastatic organotropism that persist after correction for mutational burden. Tumors from patients with liver metastases showed significantly higher prevalence (p &amp;lt; 0.05) of mutation compared to patients without liver metastases in KMT2D (56% vs 18%), BCL6 (22% vs 0%), TMPRSS2 (22% vs 0%), ARID1B (33% vs 4%), MET (33% vs 4%), and AXL (44% vs 11%), with similar enrichment in the liver met-predominant metastatic cluster, implicating dysregulation of histone and protein deacetylation pathways in liver metastatic organotropism (p &amp;lt; 0.01). Numerous additional mutational correlates were found for the remaining nine metastatic sites and all five metastatic patterns, and validation in an orthogonal dataset is ongoing. We present robust stereotypic patterns of metastasis and both site- and pattern-specific genomic correlates of organotropism in metastatic melanoma. By leveraging a valuable clinical/genomic data set, we nominate genetic correlates of organotropism for functional validation and potential therapeutic targets. Citation Format: William H. Ge, Giuseppe Tarantino, Emily Robitschek, Michael P. Manos, Lauren Eastman, Olivia Ouyang, Patrick Ott, Ann W. Silk, Osama E. Rahma, Alexander Gusev, Rizwan Haq, Elizabeth I. Buchbinder, Megan L. Insco, Stephen Hodi, Eliezer Van Allen, David Liu. Stereotypic patterns and genomic correlates of organotropism in metastatic melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2846.

Angiogenic and T-effector subgroups identified by gene expression profiling (GEP) and propensity for PBRM1 and BAP1 alterations in clear cell renal cell carcinoma (ccRCC).

343 Background: With the emergence of multiple active treatment options in RCC, predictive biomarkers for optimal treatment selection are lacking. Gene expression data from IMmotion151 and Javelin Renal 101 clinical trials generated anti-angiogenic and immune signatures that warrant further validation. We aimed to describe the genomic and gene expression profiles in a multi-institutional database of patients with ccRCC, and its association with other biomarkers of interest. Methods: Whole transcriptome sequencing was performed for ccRCC patient samples submitted to a commercial CLIA-certified laboratory (Caris Life Sciences, Phoenix, AZ) from February 2019 to September 2020. Tumor GEP and hierarchical clustering based on the validated 66-gene signature (D’Costa et al, 2020) were used to identify patient subgroups. Samples from both primary tumors and metastatic sites were included. Results: A total of 316 patients with ccRCC, median age 62 (range 32-90), 71.8% men, were included. Tissue samples were obtained from primary tumor (46.5%), lung (12.3%), bone (9.5%), liver (4.7%) and other metastatic sites (27%). Gene expression analysis identified angiogenic, mixed and T-effector subgroups in 24.1%, 51.3% and 24.7%, respectively. Patients with angiogenic subgroup tumors compared to those with T-effector subgroup tumors were more likely to be older (63 versus 60 years, p=0.035), female (40.8% versus 16.7%, p=0.0009) and more frequently found in pancreatic/small bowel metastases (75% versus 12.5%, p=0.0103). Biomarkers of potential response to immunotherapy such as PD-L1 (p=0.0021), TMB (not significant), and dMMR/MSI-H status (not significant) were more frequent in the T-effector subgroup. PBRM1 mutations were more common in the angiogenic subgroup (62.0% vs 37.5%, p=0.0034) while BAP1 mutations were more common in the T-effector subgroup (18.6% versus 3.0%, p= 0.0035). Immune cell population abundance (e.g. NK cells, monocytes) and immune checkpoint gene expression (TIM-3, PD-L1, PD-L2, CTLA4) were also increased in the T-effector subgroup. Conclusions: Our hierarchical clustering results based on the 66-gene expression signature were concordant with results from prior studies. Patient subgroups identified by evaluation of angiogenic and T-effector signature scores exhibit significantly different mutations and immune profiles. These findings require prospective validation in future biomarker-selected clinical trials.

TP53 fusions with next-generation sequencing (NGS) in Chinese non-small cell lung cancer (NSCLC): A multicenter study.

e21742 Background: Currently, with the advances in detection techniques, such as next generation sequencing (NGS), more and more rare or atypical TP53 fusions had been identified. Such as TP53-PSMD14, the importance of EGFR signaling in the pathogenesis of lung cancer and the efficacy of EGFR-TKI treatment had been demonstrated. The aim of this study was to evaluate the prevalence of TP53 fusions in Chinese NSCLC populations, which had not been reported earlier, and to describe targeting potential in Chinese NSCLC populations. Methods: A multicenter study in China was initiated from February 2014, and NSCLC patients have been enrolled as of December 2018. A total of 2743 patients with NSCLC were screened by using next-generation sequencing (NGS)-based 381 genes panel assay for detecting TP53 fusions. Results: Of this entire cohort, just four (0.15%) patients were identified with a TP53 fusion, including DNAH2-TP53 (1), TP53-MPDU1 (1), TP53-FXR2 (1), TP53-VEZF1 (1). Of the TP53 fusion NSCLC patients, 50.00% were detected in female patients. Biopsies were obtained from primary lung tumor (25.00%) and metastatic sites (75.00%). Overall TMB in the TP53 fusion was high, which had more than 20 mut/Mb. Of the TP53 fusion NSCLC, two cases (50.00%) featured EGFR SV alterations. Conclusions: The frequency of TP53 fusions in Chinese populations with NSCLC is extremely rare (0.17%). TP53 fusions may reduce responsiveness to TKIs and worsen prognosis in EGFR-mutated NSCLC patients, mainly those carrying exon 19 deletions or exon 21 L858R.

Prognosis of Patients With Testicular Carcinoma Is Dependent on Metastatic Site.

Background: Existing data on the association of metastatic sites and prognosis of patients with metastatic testicular malignancy are limited. In this study, the association of survival outcome and the prognostic value of different metastatic sites in patients with metastatic testicular cancer was investigated.Methods: A dataset from the Surveillance, Epidemiology and End Results (SEER) survey was selected for a retrospective metastatic testicular cancer cohort study. Patients with different metastatic sites were divided into corresponding groups for further analysis. Kaplan-Meier analysis with log-rank test was implemented for comparison of the survival distribution of cases. Multivariate Cox regression models were then applied to analyze the association of distant metastases with survival for all selected patients and subgroup based on different histological type with a single metastatic site.Results: A total of 1,661 patients treated for metastatic testicular malignant tumors between 2010 to 2016 were enrolled in this cohort study. Upon initial diagnosis, 61.9, 15.2, 6.7, 6.4, and 36.2% of patients were found to have lung, liver, bone, brain, and distant lymph nodes metastatic sites, respectively. Patients with lung, liver, or bone metastases showed more undesirable prognosis for overall survival (OS) and cancer-specific survival (CSS), in contrast with those with distant lymph node metastases (all P < 0.05). In comparison with patients with more than one metastatic site, those with a single metastasis had extended OS and CSS (both P < 0.001). In patients with a single metastatic site, Kaplan-Meier analysis and multivariate Cox regression demonstrated the association of bone and liver with the worst two groups of OS and CSS. Multivariate Cox models based on histological type showed different prognostic values of metastases in patients with seminoma or non-seminomatous germ cell tumors.Conclusion: There is much heterogeneity in the oncological outcome of site-specific metastatic patients. Metastatic profiles and the prognostic value of metastases are dependent on the histological type in TC patients. Distant lymph nodes and lung metastases indicate favorable prognostic factors, while bone and liver metastases indicate negative survival outcomes in TC.

Pre-metastatic niche triggers SDF-1/CXCR4 axis and promotes organ colonisation by hepatocellular circulating tumour cells via downregulation of Prrx1

BackgroundCirculating tumour cells (CTCs), especially mesenchymal CTCs, are important determinants of metastasis, which leads to most recurrence and mortality in hepatocellular carcinoma (HCC). However, little is known about the underlying mechanisms of CTC colonisation in pre-metastatic niches.MethodsDetection and classification of CTCs in patients were performed using the CanPatrol™ system. A lentiviral vector expressing Prrx1-targeting shRNA was constructed to generate a stable HCC cell line with low expression of Prrx1. The effect of Prrx1 knockdown on stemness, migration, and drug resistance of the cell line was assessed, including involvement of SDF-1/CXCR4 signalling. Promising clinical applications of an inhibitor of STAT3 tyrosine phosphorylation, C188–9, and specific blockade with CXCR4 antibody were explored.ResultsThe number of mesenchymal CTCs in blood was closely associated with tumour recurrence or metastasis. Pre-metastatic niche-derived SDF-1 could downregulate Prrx1, which induced the stemness, drug resistance, and increased expression of CXCR4 in HCC cells through the STAT3 pathway in vitro. In vivo, mice bearing tumours of Prrx1 low-expressing cells had significantly shorter survival. In xenograft tumours and clinical samples, loss of Prrx1 was negatively correlated with increased expression of CXCR4 in lung metastatic sites compared with that in the primary foci.ConclusionsThese findings demonstrate that decreased expression of Prrx1 stimulates SDF-1/CXCR4 signalling and contributes to organ colonisation with blood CTCs in HCC. STAT3 inhibition and specific blockade of CXCR4 have clinical potential as therapeutics for eliminating organ metastasis in advanced HCC.

Radiotherapy may improve survival of ES-SCLC with distant metastasis only for patients with one metastatic site: A population-based study.

The aim of the present study was to investigate the prognostic impact of RT on patients with extensive stage small cell lung cancer (ES-SCLC) and distant metastasis. Using the Surveillance Epidemiology and End Results (SEER) database, 8,595 patients with ES-SCLC exhibiting distant metastasis treated between 2010 and 2013 were identified. Patient baseline characteristics were compared using the χ2 test. The Kaplan-Meier test was used to analyze subgroup cancer-specific survival (CSS) rate, and differences were compared using a log-rank test. Univariate and multivariate Cox regression models were used to analyze the prognostic variables on CSS. RT was determined to be an independent prognostic factor for patient CSS (P<0.001). In addition, RT could improve the CSS of patients with ES-SCLC with one metastatic lesion (hazard ratio, 0.63; 95% confidence interval, 0.59–0.68; P<0.001), including the bone, brain, liver and lung metastatic sites. However, for patients with two metastatic sites, RT did not improve CSS regardless of metastasis pattern (all P>0.05). To conclude, RT may improve the survival rate of patients with ES-SCLC with distant metastasis, particularly in those with only one metastatic site.

Abstract 4528: Quantitative mass spectrometry to interrogate proteomic heterogeneity in metastatic lung adenocarcinoma and validate a novel somatic mutation CDK12-G879V

Abstract Lung cancer is the leading cause of cancer mortality. Tumor heterogeneity is a major cause of treatment failure. Intra- and inter-metastatic tumor heterogeneity has been demonstrated by next generation sequencing (NGS) studies. However, heterogeneity in the proteome and phosphoproteome has been less studied. Integrated proteogenomics is essential to understanding the intricacies of tumor heterogeneity affecting treatment response. Here, we performed integrated mass spectrometry-based proteogenomics to characterize spatial and temporal heterogeneity of an exceptional responder lung adenocarcinoma patient who survived with metastatic disease for more than 7 years while on combination treatment with HER2-targeted and chemotherapy. We employed Super-SILAC and TMT labeling strategies to quantify the proteome and phosphoproteome of a lung metastatic site and ten different metastatic progressive lymph nodes from our patient collected across a span of seven years, including at autopsy. To further interrogate the mass spectrometry data, patient-specific database was built to incorporate all the somatic variants identified by NGS. An extensive validation pipeline was built for confirmation of variant peptides. CRISPR-Cas9-mediated gene knockout, cell viability assays, and confocal microscopy were used for further validation of novel variants. A total of 6214 and 4061 proteins were identified from Super-SILAC and TMT experiments, respectively. 3648 proteins were identified and quantified in both experiments. More than 2000 proteins had catalytic activity, including kinases, phosphatases and metabolic enzymes. We identified 78 and 23 mutant peptides from Super-SILAC and TMT experiments, respectively. Three somatic variants, CDK12-G879V, FASN-R1439Q and HNRNPF-A105T, were confirmed using our variant peptide detection pipeline. Multiple reaction monitoring in a triple quadrupole mass spectrometer successfully identified and relatively quantified two of the variant tryptic peptides harboring the mutations, CDK12-G879V and FASN-R1439Q from the lung and lymph node metastatic sites, respectively. We investigated the consequences of loss of CDK12 function, as predicted from the novel CDK12-G879V mutant, in chemotherapy sensitivity. A549 lung adenocarcinoma cells, upon knockdown of CDK12, exhibited greater chemotherapy sensitivity that was rescued by wild type CDK12, but not by CDK12-G879V mutant. We demonstrate the importance of integrated proteogenomic analyses to identify variant peptides in mass spectrometry data and studying proteomic heterogeneity affecting treatment response. CDK12-G879V mutation results in a nonfunctional CDK12 kinase and chemotherapy susceptibility in lung metastatic sites, likely explaining the “cure” of lung metastatic sites in this patient. Citation Format: Xu Xhang, Khoa Dang P. Nguyen, Paul Rudnick, Nitin Roper, Emily Kawaler, Tapan K. Maity, Shivangi Awasthi, Shaojian Gao, Romi Biswas, Abhilash Venugopalan, Constance Cultraro, David Fenyo, Udayan Guha. Quantitative mass spectrometry to interrogate proteomic heterogeneity in metastatic lung adenocarcinoma and validate a novel somatic mutation CDK12-G879V [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4528.