Oncogene Mutation Status Research Articles

Prediction of oncogene mutation status in non-small cell lung cancer leveraging radiomics from CT scans: A systematic review and meta-analysis with a special focus on artificial-intelligence-based methods.

e20603 Background: In non-small cell lung cancer (NSCLC), alternative strategies to determine patient oncogene mutation status are essential to overcome some of the drawbacks associated with current methods. We aimed to review the use of radiomics alone or in combination with clinical data and to evaluate the performance of artificial intelligence (AI)-based models on the prediction of oncogene mutation status. Methods: A PRISMA-compliant literature review was conducted. The Medline (via Pubmed), Embase, and Cochrane Library databases were searched for studies published through June 30, 2023, predicting oncogene mutation status in patients with NSCLC using radiomics. Independent meta-analyses evaluating the performance of AI-based models developed with radiomics features or with a combination of radiomics features plus clinical data for the prediction of different oncogenic driver mutations were performed. A meta-regression to analyze the influence of methodological/clinical factors was also conducted. Results: Out of the 615 studies identified, 89 evaluating models for the prediction of epidermal growth factor-1 (EGFR), anaplastic lymphoma kinase (ALK), and Kirsten rat sarcoma virus (KRAS) mutations were included in the systematic review, including a total of 32,084 patients. A total of 38 met the inclusion criteria for the meta-analyses (encompassing 17,066 patients). The AI algorithms' sensitivity/false positive rate (FPR) in predicting EGFR, ALK, and KRAS mutations using radiomics-based models was 0.753 (95% CI 0.721–0.783)/0.346 (95% CI 0.305–0.390), 0.754 (95% CI 0.639–0.841)/ 0.225 (95% CI 0.163–0.302), and 0.744 (95% CI 0.605–0.846)/0.376 (95% CI 0.274–0.491), respectively. A meta-analysis of combined models was only possible for EGFR mutation, revealing a sensitivity/FPR of 0.800 (95% CI 0.767–0.830)/0.335 (95% CI 0.279–0.396). No statistically significant results were obtained in the meta-regression. Conclusions: Radiomics with a specific focus on CT-based models may represent valuable non-invasive tools for the determination of oncogene mutation status in NSCLC. Further investigation is required to analyze whether clinical data might boost their performance.

A New Perspective on the Effectiveness of FDG PET/CT in Predicting KRAS Mutation in Colon Cancer Cases.

Aim: The main aim of this study was to evaluate the effectiveness of 18F-fluorodeoxyglucose (18FDG) positron emission tomography/computerized tomography (PET/CT) parameters in predicting the Kristen rat sarcoma viral oncogene(KRAS) mutation status of patients with colon cancer. Materials and Methods: Between April 2013 and December 2020, 79 patients who were diagnosed with colon cancer by colonoscopy underwent staging 18FDG PET/CT with this diagnosis and met all the inclusion criteria were included in this study. Clinical and prognostic features and also imaging (18FDG PET/CT and magnetic resonance imaging) reports of the patients were collected and analyzed retrospectively. Results: KRAS mutation was seen in 32 of patients (40.5%). No significant difference was observed between KRAS mutant and wild-type patients in terms of clinical features (tumor location, findings regarding metastasis, T stage, and tumor differentiation grade in patients who underwent surgery) and overall survival. Progression-free survival was significantly shorter in KRAS mutant patients (p = 0.018). Primary tumor standardized uptake value (SUVmean) was significantly higher in KRAS mutant cases in the whole group (p = 0.024) and in patients in whom KRAS analysis was performed only in the primary lesion (p = 0.036). The cutoff value for predicting KRAS mutation status was 7.01 g/mL (area under the curve [AUC]: 0.650, confidence interval [CI] 95%, 0.56-0.74). Conclusions: When colon and rectal cancer cases were evaluated separately, the primary tumor SUVmean value was significantly higher in KRAS mutant colon cancer cases. However, its effectiveness in predicting KRAS mutation status was low, similar to other parameters in the literature.

Does RAS Status Increase the Prevalence of Positive Resection Margin in Colorectal Liver Metastasis? A Systematic Review and Meta-Analysis.

Colorectal liver metastasis has a high incidence, and RAS oncogene mutation status carries significant prognostic information. We aimed to assess whether RAS-mutated patients present more or less frequently with positive margins in their hepatic metastasectomy. We performed a systematic review and meta-analysis of studies from PubMed, Embase, and Lilacs databases. We analyzed liver metastatic colorectal cancer studies, which included information on RAS status and had surgical margin analysis of the liver metastasis. Odds ratios were computed using a random-effect model due to anticipated heterogeneity. We further performed a subanalysis limited to studies that included only patients with KRAS instead of all-RAS mutations. From the 2,705 studies screened, 19 articles were included in the meta-analysis. There were 7,391 patients. The prevalence of positive resection margin was not significantly different between patients carrier vs non-carrier for the all-RAS mutations (OR .99; 95% CI 0.83-1.18; P = .87), and for only KRAS mutation (OR .93; 95% CI 0.73-1.19; P = .57). Despite the strong correlation between colorectal liver metastasis prognosis and RAS mutation status, our meta-analysis's results suggest no correlation between the RAS status and the prevalence of positive resection margins. The findings contribute to a better understanding of the RAS mutation's role in the surgical resections of colorectal liver metastasis.

Predictive biomarkers for response to trametinib in non-small cell lung cancer.

Non-small cell lung cancer (NSCLC) is a leading cause of cancer deaths. Current companion diagnostics use driver mutation sequencing to select patients for molecularly targeted agents (MTA), even though most patients lack actionable mutations. These diagnostics utilize static biomarkers, ignoring real-time tumor cell biology. Trametinib is FDA-approved in combination with dabrafenib for BRAF V600E-positive NSCLC, however, it has plausible utility beyond these patients. We sought to identify novel biomarkers for maximizing trametinib application. Trametinib responses were evaluated in 12 EGFR/BRAF wild-type (WT) NSCLC cell lines with diverse RAS mutational status. We identified three response categories by colony assay. Trametinib-induced molecular dynamics were studied using immunoassays and apoptosis/necrosis assays, to identify predictive response biomarkers. p27 accumulation and cyclin D1 downregulation suggested universal cell cycle arrest with trametinib. However, 4 cell lines showed PARP cleavage and 8 showed increased phospho-4E-BP1, suggesting varied cellular outcomes from apoptosis, necrosis, senescence to autophagy. Cleaved PARP, phospho-4E-BP1 and phospho-AKT expression can predict these outcomes. Trametinib monotherapy outcome may depend upon cellular context more than oncogenic mutation status. In BRAF WT NSCLC, trametinib may be best suited for combination therapy and dynamic biomarkers could select combinations and predict responses.

Final efficacy outcomes of atezolizumab with chemoradiation for unresectable NSCLC: The phase II DETERRED trial

IntroductionThe phase II DETERRED trial assessed the safety and efficacy of consolidation and concurrent immunotherapy with chemoradiation in unresectable locally advanced non-small cell lung cancer. We present updated efficacy analysis of this trial. MethodsThe trial was conducted in 2 parts with patients in part 1 (n = 10) receiving chemoradiation with consolidation atezolizumab, while patients in part 2 (n = 30) received concurrent and consolidation atezolizumab. Progression-free survival (PFS), time to second progression (PFS2), and overall survival (OS) were assessed using Kaplan-Meier analysis. Subset analyses were performed by programmed cell death ligand-1 (PD-L1) status and targetable driver oncogene mutation status. ResultsAt a median follow-up of 39.2 months, the median PFS for part 1 was 18.9 months and 15.1 months for part 2. Median OS for part 1 was 26.5 months and was not reached for part 2. For the cohort, 3-year OS was 53.8%, while 4-year OS was 47.4%. Patients with targetable driver oncogene mutations had a median PFS of 9.4 months and OS of not reached compared to 16.6 months (HR: 3.49, p = 0.02) and 26.9 months (HR: 0.40, p = 0.12) respectively compared to those without targetable driver oncogene mutations. Patients with PD-L1 < 1% had median PFS of 11.0 months and OS of 26.5 months compared to 27.4 months (HR: 2.01, p = 0.10) and not reached (HR: 1.49, p = 0.41) respectively for those with PD-L1 ≥ 1%. ConclusionsIn the DETERRED trial, chemoradiation with concurrent and/or consolidative atezolizumab led to comparable efficacy as consolidative durvalumab in the PACIFIC trial. The presence of targetable driver oncogene mutations led to worse PFS, while PD-L1 < 1% trended to worse PFS.

Correlations among KRAS Mutation, Microsatellite Instability, and 18F-FDG Uptake in Colon Cancer.

This study aimed to evaluate the correlation of the maximum standardized uptake value (SUVmax) with the Kirsten ras sarcoma viral oncogene (KRAS) mutation and microsatellite instability (MSI) status in colon cancer. This retrospective study included 195 patients with colon cancer who underwent 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET/CT) before surgery between January 2014 and December 2017. All patients underwent KRAS mutation and MSI analyses using surgical specimens of the primary tumor. The associations of SUVmax with KRAS mutation and MSI were analyzed. The SUVmax differed significantly between the microsatellite stable (MSS) and MSI groups (14.5 ± 7.0 vs. 19.1 ± 10.9; P = 0.0249), and between the KRAS wild-type and KRAS mutation groups (14.1 ± 7.6 vs. 17.5 ± 7.9; P = 0.0017). SUVmax obtained using 18F-FDG PET/CT showed significant differences in relation to KRAS mutation and MSI status. 18F-FDG PET/CT could be used as a supplemental modality for assessing KRAS mutations and MSI status in colon cancer.

The Number of Intraoperative Intestinal Venous Circulating Tumor Cells Is a Prognostic Factor for Colorectal Cancer Patients.

Purpose To assess the association between intestinal venous blood (IVB) circulating tumor cells (CTCs) and clinicopathological parameters in stage I-III colorectal cancer (CRC) patients. Methods Participants were retrospectively retrieved, who were admitted to our hospital or took annual physical exams between December 1, 2015 and December 31, 2018. A negative enrichment-immunofluorescence in situ hybridization (NE-imFISH) technique was used to isolate and identify CTCs. Receiver operating characteristic (ROC) curves and Youden index values were used to determine the critical CTC cutoff value for the diagnosis of CRC. Kaplan-Meier and log-rank methods were used to conduct survival analyses, and multivariate Cox regression analyses were employed for multivariate corrections to comprehensively evaluate the value of CTCs in the diagnosis of CRC. Relationships between IVB CTCs, clinicopathological parameters, and prognosis were then analyzed based upon patient postoperative follow-up data. Results In total, we retrieved 282 patients including 48 healthy controls, 72 patients with benign colorectal tumors, and 162 CRC patients. CRC patients exhibited significantly higher numbers of CTCs relative to control patients or those with benign disease. CTC numbers in CRC patient peripheral blood (PB) and IVB were closely associated with tumor node metastasis (TNM) staging (P < 0.01), carbohydrate antigen-125 (CA-125) levels (P < 0.001), and KRAS (Kirsten rat sarcoma virus oncogene) mutation status (P < 0.001). The disease-free survival (DFS) of patients in the CTC-negative group was significantly longer than that of patients in the CTC-positive group (24.60 ± 13.31 months vs. 18.70 ± 10.19 months, P < 0.05), with the same being true with respect to their overall survival (OS) (30.60 ± 12.44 months vs. 35.25 ± 11.57 months, P < 0.05). A multivariate analysis revealed that the detection ≥2 CTCs/3.2 ml was independently associated with poorer DFS and OS. CTC counts were independently predictive of CRC patients TNM staging, CA-125, and KRAS mutation status in both univariate and multivariate Cox proportional hazards regression analyses. Conclusion CTCs are valuable biomarkers that can be monitored to predict CRC patient disease progression.

Ferroptosis Mediation Patterns Reveal Novel Tool to Implicate Immunotherapy and Multi-Omics Characteristics in Bladder Cancer.

Background: The regulatory role of ferroptosis in malignant tumours has been recently demonstrated. However, the potential roles of ferroptosis mediation patterns in bladder cancer remain elusive. Materials and Methods: The ferroptosis mediation patterns of 889 bladder cancer samples were comprehensively evaluated based on ferroptosis-related genes. The underlying correlations between these mediation patterns and multi-omic characteristics of bladder cancer were systematically analysed. The ferroptosis mediation patterns of individual samples were quantified by ferropscore using the principal component analysis algorithm. The typical ferroptosis-related genes with prognostic roles were further randomly validated using immunohistochemical staining, real-time polymerase chain reaction and western blotting. Results: Three different ferroptosis mediation patterns were identified. The abundance of infiltration of 23 immune cells was different among the three mediation patterns. The quantification of ferroptosis mediation patterns in individual samples served as a promising tool for predicting patient survival outcomes; immune cell infiltration abundance; tumour mutation burden; oncogenic mutation status and tumour grade, stage and molecular subtypes. Low ferropscore combined with high tumour mutation burden was associated with the best survival prognosis. Expressions of PD-L1 (p < 0.001), PD-1 (p = 0.002) and CTLA-4 (p = 0.003) were all significantly upregulated in the high ferropscore group. Low ferropscores also predicted good immunotherapy response for anti-CTLA4 strategy. The mRNA and protein levels of FADS2, a typical ferroptosis-related gene used in the study, were higher in bladder cancer cell lines than in controlled SV-HUC-1 cells. In addition, immunohistochemical staining revealed significantly higher expression levels of FADS2 in human bladder cancer tumour tissues than in normal tissues. Conclusion: This study identified three distinct ferroptosis mediation patterns in bladder cancer. Quantification of ferroptosis mediation patterns in individual samples may help to improve the understanding of multiomic characteristics and guide future immunotherapy responses to bladder cancer.

KRAS Oncogene Mutations in Colorectal Cancer Patients in a Nepalese Tertiary Care Hospital

Colorectal cancer is one of the most common cancers in the world and ranks among top ten cancer in Nepal. Limited data have been reported in the literature regarding the prevalence of Kristen Rat Sarcoma viral oncogene mutation in Nepalese patients with colorectal cancer. In a low income country such as Nepal where majority of cancer patient pay for treatment out-of-pocket, it is important to ascertain Kristen Rat Sarcoma viral oncogene mutation status before starting treatment with these agents. We analysed 22 colorectal cancer specimens diagnosed histopathologically. Real Time Polymerase Chain Reaction was performed on extracted DNA using RoterGene from Qiagen. US Food and Drug Administration approved kit was used for detection of Kristen Rat Sarcoma viral oncogene mutation i.e. TheraScreen: K-RAS Mutation Kit: The K-RAS Kit detects seven Kristen Rat Sarcoma viral oncogene mutations in codons 12 and 13 of the Kristen Rat Sarcoma viral oncogene. Kristen Rat Sarcoma viral oncogene mutation was observed in 13 (59%) of the samples studied. All samples had point mutation on codons 12 while 5 samples (38%) also had a point mutation on codons 13. No association was found between the presence of Kristen Rat Sarcoma viral oncogene mutation and gender or age or sidedness of the cancer. Kristen Rat Sarcoma viral oncogene was commonly present in colorectal cancer specimens. Further efforts towards establishment of diagnostic test, generation of new database, development and scale up of laboratory services are needed throughout the nation.

Signatures Beyond Oncogenic Mutations in Cell-Free DNA Sequencing for Non-Invasive, Early Detection of Cancer.

Early detection of cancer saves lives, but an effective detection strategy in public health settings requires a delicate balance - periodic screening should neither miss rapidly progressing disease nor fail to detect rare tumors at unusual locations; on the other hand, even a modest false positive rate carries risks of over-diagnosis and over-treatment of relatively indolent non-malignant disease. Genomic profiling of cell-free DNA from liquid biopsy using massively parallel sequencing is emerging as an attractive, non-invasive screening platform for sensitive detection of multiple types of cancer in a single assay. Genomic data from cell-free DNA can not only identify oncogenic mutation status, but also additional molecular signatures related to potential tissue of origin, the extent of clonal growth, and malignant disease states. Utilization of the full potential of the molecular signatures from cfDNA sequencing data can guide clinical management strategies for targeted follow-ups using imaging or molecular marker-based diagnostic platforms and treatment options.

Reevaluating the prognostic value of RAS mutation status in patients with resected liver metastases from colorectal cancer: A systematic review and meta-analysis.

Although the value of Rat Sarcoma Oncogene (RAS) mutation status in predicting long-term outcomes in patients with colorectal liver metastases (CRLM) is widely accepted, the magnitude of its impact has recently been challenged by three large cohort studies. The aim of this meta-analysis is to reevaluate the impact of RAS mutations on overall survival (OS) and disease-free survival (DFS) in patients who underwent curative-intent resection of CRLM. A comprehensive literature search was performed for studies reporting outcomes of patients undergoing curative-intent surgery stratified by RAS mutation status. Exclusion criteria were defined a priori. Subgroup analysis was performed to evaluate the effect of publication date, sample size, and KRAS vs any RAS mutation on overall outcomes. Ten studies incorporating 3115 patients with known RAS status were identified. Pooled results revealed significantly worse OS (Hazard Ratio 1.5, 95% CI 1.31-1.71) and DFS (Hazard Ratio 1.36, 95% CI 1.22-1.52) in RAS-mutated patients. Subgroup analyses revealed that studies including more than 300 patients or published after 2015 reported lower HR than their counterparts. The results of this meta-analysis suggest that the prognostic value of RAS mutation status in patients with CRLM has been previously overestimated.

Abstract 3276: Molecular heterogeneity of anti-PD-1/PD-L1 immunotherapy efficacy is correlated with tumor immune microenvironment in non-small cell lung cancer from East-Asian patients

Abstract Background: Anti-PD-1/PD-L1 immunotherapy is widely used to treat patients with advanced non-small-cell lung cancer (NSCLC). Although PD-1/PD-L1 inhibitor efficacy across NSCLC is now better understood, it is largely unknown how the tumor immune microenvironment differs regarding tumor genomics and its impact on prognosis and response to immunotherapy in East-Asian NSCLC patients. Methods: We performed an integrated analysis on publicly available data to explore associations between anti-PD-1/PD-L1 immunotherapy efficacy and classic driver oncogene mutations, including EGFR, KRAS, and ALK fusion mutations, in East-Asian NSCLC patients. Four pooled and clinical cohort analyses were used to correlate driver oncogene mutation status and tumor microenvironment based on PD-L1 and CD8+ tumor-infiltrating lymphocytes (TILs). Immune infiltrating patterns were also established for genomic NSCLC subgroups by CIBERSORT algorithm. Results: Based on East-Asian NSCLC patients, TIDE analysis revealed that for anti-PD-1/PD-L1 immunotherapy, EGFR-mutant and ALK-rearranged tumors may yield inferior responses; however, KRAS-mutant tumors may respond better. Pooled and clinical cohort analyses demonstrated tumor immune microenvironment heterogeneity with oncogenic addiction. Data showed remarkably higher PD-L1- and TIL-positive KRAS-mutant tumors, suggesting KRAS mutations may drive an inflammatory phenotype with adaptive immune resistance. However, the EGFR-mutant or ALK-rearranged groups showed a remarkably higher proportion of PD-L1−/TIL− tumors, suggesting an uninflamed phenotype with immunological ignorance. Notably, similar to triple wild-type NSCLC, EGFR L858R-mutant tumors positively correlated with an inflammatory phenotype, suggesting responsiveness to anti-PD-1/PD-L1 immunotherapy. Furthermore, CIBERSORT algorithm results revealed that apart from enriched CD8+ T cells, KRAS-mutant NSCLC showed a similar intratumoral immune profile to triple wild-type NSCLC. Strikingly, EGFR-mutant and ALK-rearranged tumors were characterized by enriched resting memory CD4+ T cells, as well as a lack of CD8+ and activated memory CD4+ T cells. Conclusion: Our study highlights the complex relationship between immune heterogeneity and immunotherapeutic response in East-Asian NSCLC patients regarding oncogenic addiction. Importantly, our findings provide support for individualized treatments according to NSCLC molecular subtype. Keywords: NSCLC, East-Asian, oncogene mutations, PD-1/PD-L1 inhibitors, immune landscape Citation Format: Chengming Liu, Runsen Jin, Sufei Zheng, Xinfeng Wang, Nan Sun, Jie He. Molecular heterogeneity of anti-PD-1/PD-L1 immunotherapy efficacy is correlated with tumor immune microenvironment in non-small cell lung cancer from East-Asian patients [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3276.

Fibroblast Growth Factor-14 Acts as Tumor Suppressor in Lung Adenocarcinomas.

Investigation of the molecular dynamics in lung cancer is crucial for the development of new treatment strategies. Fibroblast growth factor (FGF) 14 belongs to the FGF family, which might play a crucial role in cancer progression. We analyzed lung adenocarcinoma (LUAC) patients samples and found that FGF14 was downregulated, correlating with reduced survival and oncogenic mutation status. FGF14 overexpression in lung cancer cell lines resulted in decreased proliferation, colony formation, and migration, as well as increased expression of epithelial markers and a decreased expression of mesenchymal markers, indicating a mesenchymal to epithelial transition in vitro. We verified these findings using small interfering RNA against FGF14 and further confirmed the suppressive effect of FGF14 in a NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ immunodeficient xenograft tumor model. Moreover, FGF14 overexpressing tumor cell RNA sequencing data suggests that genes affected by FGF14 were related to the extracellular matrix, playing a role in proliferation and migration. Notably, newly identified FGF14 target genes, adenosine deaminase RNA specific B1 (ADARB1), collagen and calcium-binding epidermal growth factor domain-containing protein 1 (CCBE1), α1 chain of collagen XI (COL11A1), and mucin 16 (MUC16) expression was negatively correlated with overall survival when FGF14 was downregulated in LUAC. These findings led us to suggest that FGF14 regulates proliferation and migration in LUAC.

Estimating productivity losses for cancer patients and caregivers of cancer patients.

e19381 Background: Although cancer is a leading cause of illness in the United States, its true impact on productivity is poorly understood. Traditional approaches to capturing health-related productivity loss—e.g., the human capital method—focus on patients’ foregone wages, overlooking fringe benefits and the impacts incurred by caregivers and co-workers. Thus, the value of lost productivity is often underestimated. We sought to comprehensively estimate productivity loss incurred by working-age cancer patients and unpaid caregivers in the United States. Methods: We conducted a cross-sectional survey study of (i) non-small cell lung cancer (NSCLC) and breast cancer (BC) patients, and (ii) unpaid caregivers. To measure loss associated with absenteeism and presenteeism, participants reported pre- and post-cancer diagnosis income, hours worked, and time to complete tasks. The “multiplier effect” method was used to measure productivity loss incurred by co-workers due to patient or caregiver absenteeism and/or presenteeism. Exploratory multivariable analyses controlled for cancer type, stage, age, time since diagnosis, oncogene mutation status, and industry sector. Results: A total of 404 participants (104 BC, 100 NSCLC patients; 100 BC, 100 NSCLC caregivers) completed the surveys. Of these, 319 participants (162 BC, 157 NSCLC) who worked ≥40 weeks in the year pre-diagnosis and who did not transition from part- to full-time work after diagnosis were included in the analysis. Over a third of the NSCLC (33%) and BC (43%) patients left the workforce after diagnosis. For patients, estimated mean annual productivity loss equaled $123,792 (144% of mean income pre-diagnosis) for NSCLC and $123,502 (209% of mean income pre-diagnosis) for BC. For caregivers, the estimated mean annual productivity loss was $90,421 (108% of mean income pre-diagnosis) for NSCLC and $143,839 (190% of mean income pre-diagnosis) for BC. Exploratory analyses also found that patient age and stage at diagnosis were positively correlated with a greater absenteeism effect. Conclusions: This study found that traditional approaches, such as the human capital method, significantly underestimate productivity loss in cancer patients and caregivers. Holistic approaches that include lost wages, fringe benefits, and teamwork effects, are better approaches to understanding the amplified impact cancer can have for patients, caregivers, and co-workers.

Oncolytic adenovirus ORCA-010 increases the type 1 T cell stimulatory capacity of melanoma-conditioned dendritic cells.

SummaryImmune checkpoint blockade has resulted in durable responses in patients with metastatic melanoma, but only in a fraction of treated patients. For immune checkpoint inhibitors (ICI) to be effective, sufficient infiltration with tumor‐reactive T cells is essential. Oncolytic viruses (OV) selectively replicate in and lyse tumor cells and so induce an immunogenic form of cell death, providing at once a source of tumor‐associated (neo)antigens and of danger signals that together induce effective T cell immunity and tumor infiltration. Melanoma‐associated suppression of dendritic cell (DC) differentiation effectively hampers OV‐ or immune checkpoint inhibitor (ICI)‐induced anti‐tumor immunity, due to a consequent inability to prime and attract anti‐tumor effector T cells. Here, we set out to study the effect of ORCA‐010, a clinical stage oncolytic adenovirus, on DC differentiation and functionality in the context of human melanoma. In melanoma and monocyte co‐cultures, employing a panel of five melanoma cell lines with varying origins and oncogenic mutation status, we observed clear suppression of DC development with apparent skewing of monocyte differentiation to a more M2‐macrophage‐like state. We established the ability of ORCA‐010 to productively infect and lyse the melanoma cells. Moreover, although ORCA‐010 was unable to restore DC differentiation, it induced activation and an increased co‐stimulatory capacity of monocyte‐derived antigen‐presenting cells. Their subsequent ability to prime effector T cells with a type I cytokine profile was significantly increased in an allogeneic mixed leukocyte reaction. Our findings suggest that ORCA‐010 is a valuable immunotherapeutic agent for melanoma.

Abstract P1-18-06: Targetable ERBB2 mutations independently predict an aggressive phenotype in primary, ERBB2 non-amplified, hormone receptor positive lobular breast cancer

Abstract Invasive lobular carcinoma accounts for 10-15% of breast cancer cases and typically expresses hormone receptors. Despite this, lobular tumours respond less well to endocrine therapy, and long-term patient outcomes are inferior to those with other breast cancer subtypes. In primary lobular tumours, HER2 is rarely overexpressed due to relative infrequency of ERBB2 amplification. However, somatic mutation of ERBB2 may provide an alternative and tractable mechanism for upregulation of HER2 activity, which can be effectively targeted using a second generation HER2/EGFR tyrosine kinase inhibitor such as neratinib. In this study we performed comparative in silico analysis of ER/PR(+), HER2(-) cases of invasive lobular (N=352) and ductal carcinoma (N=1,820) from the three largest primary breast cancer clinical datasets with somatic mutations called from next generation sequencing (TCGA, METABRIC and MSK, N=2,172). Using existing functional data from in vitro, cell line and xenograft experiments, ERBB2 mutations were stratified into known ‘oncogenic‘ or ‘uncharacterized‘ and integrated with lymph node status, tumour size and grade. The primary endpoint was overall survival as these data were available across datasets. We find that lobular tumours comprise 11% of all cases but contain 40% of the somatic mutations in ERBB2 in the dataset. The overall rate of mutated ERBB2 in lobular cases is 6% (N=21) versus 1.8% (N=32) in ductal cases (p&amp;lt;0.0001). Using a Cox regression model, we show that oncogenic ERBB2 mutation status independently predicts overall poor survival only in lobular cases (HR 3.6, 95% CI 1.57 - 8.26; p=0.0026). For patients with lobular disease, overall survival was significantly lower if tumours harboured oncogenic ERBB2 mutation (median 64 versus 170 months, p&amp;lt;0.0002). We conclude that ERBB2 mutations are enriched in ERBB2 non-amplified, ER/PR(+) lobular tumours and predict poor outcome despite use of adjuvant endocrine therapy according to standard protocols. Targeted sequencing of ERBB2 should be available for patients with lobular breast cancer and represents an actionable strategy to improve patient outcomes. Citation Format: Sasagu Kurozumi, Andrew R Green, Ian O Ellis, Emad A Rakha, Takaaki Fujii, Ken Shirabe, David Heery, Wilbert Zwart, Steffi Oesterreich, Simon J Johnston. Targetable ERBB2 mutations independently predict an aggressive phenotype in primary, ERBB2 non-amplified, hormone receptor positive lobular breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-18-06.

Molecular heterogeneity of anti-PD-1/PD-L1 immunotherapy efficacy is correlated with tumor immune microenvironment in East Asian patients with non-small cell lung cancer.

Objective: The aim of this study was to investigate how the tumor immune microenvironment differs regarding tumor genomics, as well as its impact on prognoses and responses to immunotherapy in East Asian patients with non-small cell lung cancer (NSCLC).Methods: We performed an integrated analysis using publicly available data to identify associations between anti-programmed death 1 (PD-1)/ programmed death-ligand 1 (PD-L1) immunotherapy efficacy and classic driver oncogene mutations in East Asian NSCLC patients. Four pooled and clinical cohort analyses were used to correlate driver oncogene mutation status and tumor microenvironment based on PD-L1 and CD8+ tumor-infiltrating lymphocytes (TILs). Immune infiltrating patterns were also established for genomic NSCLC subgroups using the CIBERSORT algorithm.Results: Based on East Asian NSCLC patients, TIDE analyses revealed that for anti-PD-1/PD-L1 immunotherapy, epidermal growth factor receptor (EGFR)-mutant and anaplastic lymphoma kinase (ALK)-rearranged tumors yielded inferior responses; however, although Kirsten rat sarcoma viral oncogene homolog (KRAS)-mutant tumors responded better, the difference was not statistically significant (EGFR: P = 0.037; ALK: P < 0.001; KRAS: P = 0.701). Pooled and clinical cohort analyses demonstrated tumor immune microenvironment heterogeneities correlated with oncogenic patterns. The results showed remarkably higher PD-L1- and TIL-positive KRAS-mutant tumors, suggesting KRAS mutations may drive an inflammatory phenotype with adaptive immune resistance. However, the EGFR-mutant or ALK-rearranged groups showed a remarkably higher proportion of PD-L1-/TIL-tumors, suggesting an uninflamed phenotype with immunological ignorance. Notably, similar to triple wild-type NSCLC tumors, EGFR L858R-mutant tumors positively correlated with an inflammatory phenotype, suggesting responsiveness to anti-PD-1/PD-L1 immunotherapy (P < 0.05). Furthermore, the CIBERSORT algorithm results revealed that EGFR-mutant and ALK-rearranged tumors were characterized by an enriched resting memory CD4+ T cell population (P < 0.001), as well as a lack of CD8+ T cells (P < 0.01), and activated memory CD4+ T cells (P = 0.001).Conclusions: Our study highlighted the complex relationships between immune heterogeneity and immunotherapeutic responses in East Asian NSCLC patients regarding oncogenic dependence.

Tailoring ablation strategies for colorectal liver metastases based upon rat sarcoma viral oncogene mutation status

Rat sarcoma viral oncogene (RAS) is one of the most well-known tumor genes implicated in the oncological and surgical management of patients with colorectal liver metastases (CLM). More recently, RAS mutational status has also emerged as a relevant factor affecting the oncological outcomes of CLM treated with ablation procedures, a well-established local therapy modality routinely utilized in the oligometastatic disease (OMD) setting. Available evidence suggests that RAS mutation is a prognosticator of shorter local tumor progression free survival (LTPFS) following liver ablation, and that mutant RAS patients with CLM treated with ablation should have wider minimal ablation margins. In this review, we aim to discuss the current literature on the influence of RAS mutational status on ablation outcomes, as well to provide a perspective on the future research on the impact of tumor molecular biology on liver ablation procedures and the potential synergies between local and systemic therapies.

SREBP1-dependent de novo fatty acid synthesis gene expression is elevated in malignant melanoma and represents a cellular survival trait

de novo fatty acid biosynthesis (DNFA) is a hallmark adaptation of many cancers that supports survival, proliferation, and metastasis. Here we elucidate previously unexplored aspects of transcription regulation and clinical relevance of DNFA in cancers. We show that elevated expression of DNFA genes is characteristic of many tumor types and correlates with poor prognosis, especially in melanomas. Elevated DNFA gene expression depends on the SREBP1 transcription factor in multiple melanoma cell lines. SREBP1 predominantly binds to the transcription start sites of DNFA genes, regulating their expression by recruiting RNA polymerase II to promoters for productive transcription elongation. We find that SREBP1-regulated DNFA represents a survival trait in melanoma cells, regardless of proliferative state and oncogenic mutation status. Indeed, malignant melanoma cells exhibit elevated DNFA gene expression after the BRAF/MEK signaling pathway is blocked (e.g. by BRAF inhibitors), and DNFA expression remains higher in melanoma cells resistant to vemurafenib treatment than in untreated cells. Accordingly, DNFA pathway inhibition, whether by direct targeting of SREBP1 with antisense oligonucleotides, or through combinatorial effects of multiple DNFA enzyme inhibitors, exerts potent cytotoxic effects on both BRAFi-sensitive and -resistant melanoma cells. Altogether, these results implicate SREBP1 and DNFA enzymes as enticing therapeutic targets in melanomas.

Abstract 1055: Evaluation of immune checkpoint inhibitor efficacy in EGFR mutant tumors

Abstract Tyrosine Kinase Inhibitor (TKI) of Epidermal Growth Factor Receptor (EGFR) is a first-line therapy for non-small cell carcinoma lung cancer patients with EGFR mutations, but patients often develop resistance to such a target therapy. Recently several PD-1 and PD-L1 inhibitors were approved for treating NSCLC, however, it remains unclear whether EGFR mutant NSCLC would benefit from PD-1/PD-L1 treatment. PD-1 response in cancer patients is closely associated with oncogenic mutation status, tumor microenvironment, PD-L1 expression and tumor mutation burden (TMB); however, the lack of pre-clinical models limited the investigation of the checkpoint inhibitors in EGFR mutant tumors. Here we use human PBMC reconstitution system for immune-humanization, and established a series of IO-Xenograft models (IO-CDX and IO-PDX) with cancer cell lines (IO-CDX) or patient-derived tissues (IO-PDX) that contain various EGFR mutations, including EGFR 19 del, L858R, T790M, and EGFR over-expression, amplification and fusion. We treated these models with either EGFR TKI (erlotinib, afatinib or osimertinib) or nivolumab, a PD-1 inhibitor. The predictive biomarkers including PD-L1 expression and TMB were analyzed by whole exom sequencing (WES) and FACS for tumor infiltrating lymphocytes (TILs), respectively. We found that 3 TKI-resistant PDX models bearing EGFR T790M mutation exhibited lower TILs than those bearing EGFR wild type or exon 19del mutation. Of the 8 IO-CDX or IO-PDX humanized models we have examined, those exhibiting higher TILs achieved better responses to nivolumab treatment. The 3 most sensitive models are EGFR amplification (wt), EGFR over-expression (wt) and EGFR exon 19del. In contrast, the EGFR T790M model from H1975 cell line was observed with hyper-progressive disease after nivolumab treatment. We will also discuss the contribution of PD-L1 expression and TMB to nivolumab in other models. In summary, these well-established IO-CDX and IO-PDX models can provide a human-resembling immune system for of immune therapeutics and combination with targeted therapies, and help to facilitate the understanding of relationship among tumor microenvironment, driver oncogenic mutations and drug response. Citation Format: Xuzhen Tang, Li Yang, Hui Qi, Xianzhi Zhai, Fuyang Wang, Xiangnan Qiang, Jie Xu, Xiaoran Qin, Qingyang Gu, Shaoyu Yan, Qunsheng Ji. Evaluation of immune checkpoint inhibitor efficacy in EGFR mutant tumors [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 1055.