Increased Tumor Burden Research Articles

PEMBROLIZUMAB-INDUCED HYPERPROGRESSION IN PATIENT WITH NON-SMALL CELL LUNG CANCER

SESSION TITLE: Medical Student/Resident Lung Cancer Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Immunotherapy (IT) drugs are widely used in the treatment of lung cancer. Novel tumor response patterns like delayed tumor response or pseudoprogression(PP) and hyper progression (HP) are noted in patients on IT. Champiat-et-al in 2017 defined HP as a ≥ 2-fold increase of the tumor growth rate (TGR) by RECIST (response evaluation criteria) compared with pre-IT. Time to treatment failure < 2 months, > 50% increase in tumor burden and > 2-fold increase in progression pace were considered as hyper progression in some studies. The incidence of hyper progression is noted to be around 10%. CASE PRESENTATION: A 71 y/o M with h/o Rheumatoid arthritis(RA) on methotrexate, started treatment with first-line chemotherapy for stage IV non-small cell lung cancer. Immunotherapy was initially omitted given the risk of a flare of his RA. After 4 cycles of carboplatin and pemetrexed, his restating scan showed regression of lung and liver tumor burden. Given his excellent clinical response and high PD-L1 (80%), immunotherapy with pembrolizumab was added to his maintenance chemotherapy. After two weeks, he was hospitalized with hypoxic and hypercarbia respiratory failure, and repeat computed tomography(CT) showed a two-fold increase in the size of the preexisting tumors with new large multiloculated right pleural effusion and abdominal ascites. He was treated with empiric antibiotics, high dose steroids, and supportive care, but he passed away in 2 days. DISCUSSION: Pseudoprogression(PP) of cancer on immunotherapy is a phenomenon where there is an initial growth in the tumor size before regression with continued treatment, clinical improvement in patient symptoms, without new metastases. Hyperprogression is a rapid growth of the tumor in a very short interval causing significant clinical deterioration. The mechanism of hyperprogression is not fully understood, possible hypotheses include oncogenic signaling activation, upregulation of alternative immune checkpoints, or modulation of other protumor immune subsets. There are no biomarkers identified that can predict an individual’s response to immunotherapy. During treatment with immunotherapy, if pseudo or hyperprogression is unclear, immunotherapy should be stopped immediately, and chemotherapy should be initiated rapidly to gain control of the tumor growth. The goal of immunotherapy in NSCLC is to shift the immune balance in favor of activation so that the host may launch a response to tumor-associated antigens. Immunotherapy agents like nivolumab, pembrolizumab, and atezolizumab are the mainstay of treatment for advanced NSCLC. Despite recent advancements, more than half of the patients die within 1 year and 5-year survival of around 17.8%. CONCLUSIONS: This case emphasizes that physicians need to be aware of the new tumor response patterns to IT like HP and PP, and rapidly distinguishing between both could make a significant clinical impact on patient outcomes. Reference #1: Champiat S, Dercle L, Ammari S, Massard C, Hollebecque A, Postel-Vinay S, Chaput N, Eggermont A, Marabelle A, Soria J-C, et al. Hyperprogressive disease is a new pattern of progression in Cancer patients treated by anti-PD-1/PD-L1. Clin Cancer Res. 2017;23(8):1920–8 Reference #2: Woo EY, Chu CS, Goletz TJ, et al. Regulatory CD4(+)CD25(+) T cells in tumors from patients with early-stage non-small cell lung cancer and late-stage ovarian cancer. Cancer Res 2001;61:4766-72 Reference #3: Woo EY, Yeh H, Chu CS, et al. Cutting edge: Regulatory T cells from lung cancer patients directly inhibit autologous T cell proliferation. J Immunol 2002;168:4272-6. 10.4049/jimmunol.168.9.4272 DISCLOSURES: No relevant relationships by vineela kasireddy, source=Web Response No relevant relationships by Shobha Mandal, source=Web Response No relevant relationships by JOYSON POULOSE, source=Web Response No relevant relationships by Layla Sulaiman, source=Web Response

Treatment after progression in the era of immunotherapy.

Immunotherapy represents a paradigm shift in oncology treatment. The goal of immunotherapy is to overcome immunosuppression induced by a tumour and its microenvironment, thereby allowing the immune system to target and kill cancer cells. The immunotherapy era began when the first immune checkpoint inhibitor, ipilimumab, was approved for use almost a decade ago. This therapeutic approach is associated with distinct types of response, including processes such as pseudoprogression (ie, increased tumour burden via radiology, which is not accompanied by clinical deterioration) and hyperprogression (ie, rapid progression of the disease as a result of immunotherapy). In this Review, we focus on therapeutic approaches for patients who progress on immunotherapy. We review the different types of clinical responses associated with immunotherapy and describe treatment options for this population.

Novel role of lncRNA CHRF in cisplatin resistance of ovarian cancer is mediated by miR-10b induced EMT and STAT3 signaling

Ovarian Cancer (OC) is a highly lethal gynecological cancer which often progresses through acquired resistance against the administered therapy. Cisplatin is a common therapeutic for the treatment of OC patients and therefore it is critical to understand the mechanisms of resistance against this drug. We studied a paired cell line consisting of parental and cisplatin resistant (CR) derivative ES2 OC cells, and found a number of dysregulated lncRNAs, with CHRF being the most significantly upregulated lncRNA in CR ES2 cells. The findings corroborated in human patient samples and CHRF was significantly elevated in OC patients with resistant disease. CHRF was also found to be elevated in patients with liver metastasis. miR-10b was found to be mechanistically involved in CHRF mediated cisplatin resistance. It induced resistance in not only ES2 but also OVCAR and SKOV3 OC cells. Induction of epithelial-to-mesenchymal-transition (EMT) and activation of STAT3 signaling were determined to be the mechanisms underlying the CHRF-miR-10b axis-mediated cisplatin resistance. Down-regulation of CHRF reversed EMT, STAT3 activation and the resulting cisplatin resistance, which could be attenuated by miR-10b. The results were also validated in an in vivo cisplatin resistance model wherein CR cells were associated with increased tumor burden, CHRF downregulation associated with decreased tumor burden and miR-10b again attenuated the CHRF downregulation effects. Our results support a novel role of lncRNA CHRF in cisplatin resistance of OC and establish CHRF-miR-10b signaling as a putative therapeutic target for sensitizing resistant OC cells.

1986P MDM2 amplification and hyperprogression following treatment with immune checkpoint inhibitors in advanced non-small cell lung cancer

Immunotherapy either alone or in combination with chemotherapy has largely become the standard of care for patients with metastatic non-small cell lung cancer. In a small subset of patients, immune checkpoint inhibitors paradoxically can increase tumor growth and worsen overall survival, a phenomenon referred to as hyperprogression. Previous research has examined the role of MDM2 amplification as a predictor for hyperprogression across multiple different tumor types. Through its interaction and inhibition of p53, MDM2 amplification can lead to increased tumorigenesis. We sought to determine whether MDM2 amplification played a role in a cohort of NSCLCa patients who met clinical and or radiological criteria for hyperprogression. Patients were selected based on previously reported radiological criteria; time to treatment failure <2 months, >50% increase in tumor burden compared with pre-immunotherapy imaging, acceleration of tumor growth kinetics (TGK ratio >2). MDM2 amplification was determined via fluorescent in-situ hybridization (FISH). Due to the close relationship between MDM2 and p53, immunohistochemistry (IHC) staining for p53 was carried out as a confirmatory assay. 16 patients were identified as meeting previously defined criteria for hyperprogression. 9 had adenocarcinoma and 7 had squamous cell carcinoma. PDL-1 was expression was >1% in 13 patients and <1% in 3 patients. No targetable mutations were identified. 14 of the patients had a smoking history. 11 patients had tissue samples suitable for testing. No MDM2 amplification was seen with FISH in any of the 11 patients and in 10 of the 11 patients p53 staining was positive with IHC. MDM2 amplification was not observed in any of the 11 identified patients who met criteria for hyperprogression contrary to previous reports outside of a lung cancer cohort. MDM2 has been reported as a negative regulator of p53 and given that p53 however remained positive on IHC in this study suggests that MDM2 here has not suppressed the p53 tumor suppressor gene. More research is needed to further clarify the role of MDM2 and its interaction with p53 in lung cancer patients who display hyperprogression post immunotherapy.

The role and mechanism of action of RNF186 in colorectal cancer through negative regulation of NF-κB

Colorectal cancer (CRC) is one of the most common malignant gastrointestinal cancers worldwide. RING finger protein 186 (RNF186) is a member of the RING finger protein family. RNF186 has been reported to be involved in the regulation of the intestinal homeostasis through the regulation of endoplasmic reticulum (ER) stress in colonic epithelial cells. However, its role in CRC remains unclear. In this study, we found that colorectal tumours from human patients had decreased levels of RNF186. We demonstrated that overexpression of RNF186 suppressed the growth and migration of CRC-derived cell lines in vitro and inhibited tumour proliferation in vivo. Further, our findings indicated that forced expression of RNF186 inhibited nuclear factor-κB (NF-κB) activation by reducing the phosphorylation of NF-κB. In addition, our results showed that RNF186−/− mice exhibited significantly increased tumour burden compared to the wild type (WT) mice following treatment with azoxymethane/dextran sulfate sodium (AOM/DSS). Compared to WT mice, the percentage of Ki67 positive cells was increased in the RNF186−/− mice, indicating that RNF186 is crucial for intestinal cell proliferation during tumorigenesis. Taken together, our data suggest that RNF186 inhibits the development of CRC, and that this effect is mediated through the suppression of NF-κB activity.

Evaluating the efficacy of enzalutamide and the development of resistance in a preclinical mouse model of type-I endometrial carcinoma

Androgen Receptor (AR) signaling is a critical driver of hormone-dependent prostate cancer and has also been proposed to have biological activity in female hormone-dependent cancers, including type I endometrial carcinoma (EMC). In this study, we evaluated the preclinical efficacy of a third-generation AR antagonist, enzalutamide, in a genetic mouse model of EMC, Sprr2f-Cre;Ptenfl/fl. In this model, ablation of Pten in the uterine epithelium leads to localized and distant malignant disease as observed in human EMC. We hypothesized that administering enzalutamide through the diet would temporarily decrease the incidence of invasive and metastatic carcinoma, while prolonged administration would result in development of resistance and loss of efficacy. Short-term treatment with enzalutamide reduced overall tumor burden through increased apoptosis but failed to prevent progression of invasive and metastatic disease. These results suggest that AR signaling may have biphasic, oncogenic and tumor suppressive roles in EMC that are dependent on disease stage. Enzalutamide treatment increased Progesterone Receptor (PR) expression within both stromal and tumor cell compartments. Prolonged administration of enzalutamide decreased apoptosis, increased tumor burden and resulted in the clonal expansion of tumor cells expressing high levels of p53 protein, suggestive of acquired Trp53 mutations. In conclusion, we show that enzalutamide induces apoptosis in EMC but has limited efficacy overall as a single agent. Induction of PR, a negative regulator of endometrial proliferation, suggests that adding progestin therapy to enzalutamide administration may further decrease tumor burden and result in a prolonged response.

Abstract 627: Evaluating the efficacy of enzalutamide and the development of resistance in a preclinical mouse model of type-I endometrial carcinoma

Abstract Androgen Receptor (AR) signaling is a critical driver of hormone-dependent prostate cancer and has also been proposed to have biological activity in female hormone-dependent cancers, including type I endometrial carcinoma (EMC). In this study, we evaluated the preclinical efficacy of a third-generation AR antagonist, enzalutamide, in a genetic mouse model of EMC, Sprr2f-Cre;Ptenfl/fl. In this model, ablation of Pten in the uterine epithelium leads to localized and distant malignant disease as observed in human EMC. We hypothesized that administering enzalutamide through the diet would temporarily decrease the incidence of invasive and metastatic carcinoma, while prolonged administration would result in development of resistance. Short-term treatment with enzalutamide reduced overall tumor burden through increased apoptosis but failed to prevent progression of invasive and metastatic disease suggesting that AR signaling may have biphasic, oncogenic and tumor suppressive roles in EMC. Enzalutamide treatment increased Progesterone Receptor (PR) expression within both stromal and tumor cell compartments. Prolonged administration of enzalutamide decreased apoptosis, increased tumor burden and resulted in the clonal expansion of tumor cells expressing high levels of p53 protein, suggestive of acquired Trp53 mutations. In conclusion, we show that enzalutamide induces apoptosis in EMC but has limited efficacy overall as a single agent. Induction of PR, a negative regulator of endometrial proliferation, suggests that adding progestin therapy to enzalutamide administration may further decrease tumor burden and result in a prolonged response. Citation Format: Christopher Steven Koivisto, Parrish Melodie, Bonala Santosh, Soo Ngoi, Georges J. Nahhas, Bei Liu, Adrian Torres, James Gallagher, Rebekah Snchez-Hodge, Victor Zeinner, David Cohn, Floor Backes, Paul Goodfellow, Helen Chamberlin, Gustavo Leone. Evaluating the efficacy of enzalutamide and the development of resistance in a preclinical mouse model of type-I endometrial carcinoma [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 627.

Abstract LB-210: Chemotherapy promotes metastasis through extracellular vesicle secretion

Abstract Neoadjuvant chemotherapy treatment is the gold standard for children and adults with intermediate- to high-risk tumors. However, a subset of patients develop distant metastases following treatment, and evidence suggests that chemotherapy itself may promote metastasis in some patients. Indeed, utilizing xenograft mouse model of human triple-negative breast cancer, we confirm that treatment with the chemotherapeutic agent Doxorubicin decreases primary tumor growth while promoting pulmonary metastasis. The purpose of this research is to understand how chemotherapy treatment regulates tumor-derived exosomes, extracellular vesicles that are secreted by all cells and that function in cellular communication through the horizontal transfer of biologically-active molecules. Specifically, our goal is to determine how exosomes derived from chemotherapy-treated tumor cells, or ‘chemoexosomes,' regulate tumor metastasis in order to develop more effective chemotherapeutic options for cancer patients. Utilizing models of both breast cancer and pediatric neuroblastoma, we demonstrate that sublethal doses of DNA-damaging chemotherapeutic agents significantly enhance exosome secretion compared to vehicle control. Xenografted mice treated with exosomes derived from chemotherapy-treated cells demonstrate a significant acceleration in metastasis with no increase in primary breast tumor growth compared to mice treated with exosomes derived from control-treated cells or saline. Although chemoexosomes do not enhance tumor cell migration or invasion in vitro, they demonstrate tumor type-specific preferential organotropic localization to the most common sites of tumor metastasis in vivo. Mice treated with chemoexosomes prior to tail-vein injection of either neuroblastoma or breast tumor cells demonstrate a significant increase in metastatic tumor burden compared to mice pre-treated with control exosomes or saline. Through proteomic analysis, we identified differentially-expressed exosomal proteins upregulated by chemotherapy treatment. Utilizing CRISPR-Cas9-mediated gene knockout, we identified a component of the complement pathway upregulated in chemoexosomes that is critically involved in exosome-mediated metastasis. Taken together, this research proposes a novel mechanism of chemotherapy-induced metastasis by which organ-specific uptake of exosomes derived from chemotherapy-treated cells primes the pre-metastatic niche in order to create a favorable environment for metastatic tumor growth. Citation Format: Carson A. Wills, Jeffrey Sundstrom, Hong-Gang Wang. Chemotherapy promotes metastasis through extracellular vesicle secretion [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 LB-210.

Abstract 6141: Role of aldehyde dehydrogenase 1B1 in colon carcinogenesis in a newly developed mouse model

Abstract Introduction: Aldehyde dehydrogenases (ALDH), particularly ALDH1B1 has been shown to have increased expression in both human and APCMin mice colorectal tumors. Studies have proposed the use of ALDH1B1 as a potential novel human colorectal tumor marker. Previous in vitro studies have shown that ALDH1B1 plays a critical role in colon carcinogenesis. The goal of this study is to understand the in vivo role of ALDH1B1 in colon carcinogenesis using a newly developed mouse model, APCMinAldh1b1−/− mice, through characterization of its phenotype in tumor growth and development, and elucidating the underlying potential molecular mechanisms. Methods: We generated APCMinAldh1b1−/-. At 12-14 weeks old, the experimental group APCMinAldh1b1−/- (n=6) and control group APCMinAldh1b1+/+ (n=7) were euthanized. Tumor counts, size and burden for each intestinal segments were recorded. H&amp;E staining was performed and observed for tumor types and counts. Immunohistochemistry using the markers Ki-67 (proliferation), Cleave Caspase 3 (apoptosis), KRT20 (differentiation) were done in colon. IHC of retinoic acid binding proteins (anti-CRBP2 and anti-FABP5) were also performed Results: The experimental group had shown significantly higher total average intestinal tumor burden (6.8 fold) (p=0.0007) and total average tumor counts observed (3.6 fold) (p=0.02). In the colon, there was a 3.5-fold increase in average tumor burden (p=0.017) with a 2.7-fold increase in average tumor size (p=0.025)in the experimental group. We also noticed a trend of increased average tumor counts observed in the colon of the experimental group although statistically insignificant. Average tumor counts of ileum observed was 9-fold higher in experimental group with only 1 mice from control group showed observable small tumor growth which did not meet criteria for tumor size and tumor burden calculation. There were no significant differences in observable tumor counts, tumor size and tumor burden in jejunum. Histologically, all tumors were pedunculated adenocarcinomas. Many unobservable small tumors less than 1mm width and length were seen in the H&amp;E of both ileum and jejunum in the experimental and control group. In the control group, there was less observable tumors compared to the experimental group although the tumor counts on H&amp;E in both groups showed no major differences. This indicates that the tumor size in the experimental group was larger than the control group. On the contrary, average tumor counts of colon in H&amp;E were lower compared to tumor counts observed in both control and experimental groups, indicating low number of small unobservable tumors in colon. Although the tumor counts of colon on H&amp;E and observation between the two groups were statistically insignificant, we noticed a pattern of increased tumor counts in the experimental group suggesting a potential increase in tumor incidence. Immunohistochemical staining of colon is ongoing. Conclusion: ALDH1B1 reduced tumor growth rate in the ileum, and reduced tumor size in the colon suggesting its role in tumor promotion and progression. A larger number of experimental and control group is required to establish its potentially tumor-initiating role in the colon. Further characterization of ALDH1B1 in colon carcinogenesis is ongoing. We are also elucidating the role and regulation of retinoic acid signaling by ALDH1B1 in colorectal tumor growth. Citation Format: Wan Ying Tan, David. J. Orlicky, Ying Chen, Yatrik M. Shah, David C. Thompson, Vasilis Vasiliou. Role of aldehyde dehydrogenase 1B1 in colon carcinogenesis in a newly developed mouse model [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 6141.

Abstract 2198: The anti-tumor enhancement of a dendritic-cell targeting MIP3α-Gp100-Trp2 DNA vaccine by IFNα and 5-Aza-2'-deoxycytidine treatments correlates with intratumoral CCL19 but not CCL21 expression

Abstract Background: The chemokine MIP-3α (CCL20) binds to CCR6 on immature dendritic cells (DCs). DNA vaccines fusing MIP-3α to melanoma-associated antigens gp100 and/or tyrosinase-related protein 2 (Trp2) have delayed tumor growth and increased survival time in the B16F10 mouse melanoma model system compared to vaccines lacking the chemokine. To further enhance the therapeutic effects of the vaccine, our laboratory has added type-I interferon (IFNα) and 5-Aza-2'-deoxycitidine (5Aza) to the therapy. Here, we report that the enhancement previously seen by the combination of IFNα, 5Aza, and a MIP-3α-Gp100-Trp2 (MGpTrp2) DNA vaccine correlates with increases of tumor-infiltrating CD8+T-cells (CD8 TILs) and intratumoral expression of CCL19 but not CCL21. Methods: Beginning on day five post-transplantation of B16F10 melanoma, vaccine was administered intramuscularly (i.m.) by electroporation. CpG adjuvant was given two days later. 5Aza was given intraperitoneally at 1mg/kg and IFNα therapy either intratumorally or i.m. as noted. Tumor sizes, tumor growth, and mouse survival were assessed. Tumor lysate gene expression levels and tumor-infiltrating lymphocytes (TILs) were assessed by qRT-PCR and flow cytometry with intracellular cytokine staining, respectively. Results: Previous work has shown that the combination of IFNα, 5Aza, and MGpTrp2 led to significantly reduced tumor burden and overall increases in mouse survival dependent upon all three components. The addition of 5Aza and IFNα to the vaccine affected T-cell tumor infiltration, increasing the proportion of CD3+CD8+ cells in gated TILs by 92% over vaccine alone (p&amp;lt;0.0001), which correlated with tumor size (r2: 0.507; p&amp;lt;0.0001). Interferon stimulated genes such as Mx1, MHC1, CXCL10, and GranzymeB were modestly upregulated in the tumor lysate. However, CCL19, normally expressed constitutively in lymphoid tissues, was upregulated 10-fold compared to vaccine alone (p&amp;lt;0.0001) and was correlated with tumor size (r2: 0.195; p=0.002). The CCL19 receptor, CCR7, was upregulated to a lesser degree (5-fold over vaccine; p&amp;lt;0.001), and interestingly its partner chemokine CCL21 did not have significantly different expression patterns across groups (p=0.14 to vaccine). Conclusions: Efficient targeting of antigen to immature dendritic cells with a chemokine-fusion vaccine offers a potential alternative approach to classic and dendritic cell-based vaccines. Combining this approach with IFNα and 5Aza treatments significantly improved vaccine efficacy. This enhancement was correlated with CD8+ TIL recruitment and with the expression of the T-cell trafficking chemokine CCL19. Further potential therapy optimization currently undergoing investigation offers promise for this line of investigation to become a novel melanoma therapy. Citation Format: James T. Gordy, Avinaash K. Sandhu, Samuel K. Ayeh, Aakanksha Kapoor, Emily Kim, Petros C. Karakousis, Richard B. Markham. The anti-tumor enhancement of a dendritic-cell targeting MIP3α-Gp100-Trp2 DNA vaccine by IFNα and 5-Aza-2'-deoxycytidine treatments correlates with intratumoral CCL19 but not CCL21 expression [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 2198.

Thrombocytosis is associated with worse survival in patients with hepatocellular carcinoma.

Thrombocytosis is associated with more aggressive tumour biology in many malignancies. There are limited data in patients with hepatocellular carcinoma (HCC), which often occurs in patients with cirrhosis and portal hypertension. We aimed to explore the prognostic value of thrombocytosis in two cohorts of patients with HCC. We included 3561 patients from Taiwan and 1145 patients from the USA. Thrombocytopenia was defined as platelet count < 150×109 /L and thrombocytosis as ≥ 300 × 109 /L at HCC diagnosis. We used multivariable Cox proportional hazard models to identify independent predictors of survival. Thrombocytosis was present in 9.0% and 6.9% of Taiwan and USA patients respectively. Compared to patients with normal platelet counts and those with thrombocytopenia, patients with thrombocytosis had larger tumours, increased vascular invasion and a higher proportion had extrahepatic metastases in both cohorts. In multivariable analysis, thrombocytosis (aHR 1.40, 95% CI 1.23-1.60) and thrombocytopenia (aHR 1.13, 95% CI 1.04-1.23) were both associated with worse survival after adjusting for age, gender, liver disease aetiology, Child-Pugh score, maximal tumour size, tumour nodularity, vascular invasion, lymph node or distant metastasis, performance status and alpha-fetoprotein level. Patients with thrombocytosis had a median survival of 6 and 4 months in the Taiwan and USA cohorts, compared to 32 and 14 months for those with normal platelet counts and 38 and 16 months for thrombocytopenic patients. Thrombocytosis is independently associated with increased tumour burden and worse overall survival among HCC patients.

IL22BP Mediates the Antitumor Effects of Lymphotoxin Against Colorectal Tumors in Mice and Humans

Background & AimsUnregulated activity of interleukin (IL) 22 promotes intestinal tumorigenesis in mice. IL22 binds the antagonist IL22 subunit alpha 2 (IL22RA2, also called IL22BP). We studied whether alterations in IL22BP contribute to colorectal carcinogenesis in humans and mice.MethodsWe obtained tumor and nontumor tissues from patients with colorectal cancer (CRC) and measured levels of cytokines by quantitative polymerase chain reaction, flow cytometry, and immunohistochemistry. We measured levels of Il22bp messenger RNA in colon tissues from wild-type, Tnf–/–, Lta–/–, and Ltb–/– mice. Mice were given azoxymethane and dextran sodium sulfate to induce colitis and associated cancer or intracecal injections of MC38 tumor cells. Some mice were given inhibitors of lymphotoxin beta receptor (LTBR). Intestine tissues were analyzed by single-cell sequencing to identify cell sources of lymphotoxin. We performed immunohistochemistry analysis of colon tissue microarrays from patients with CRC (1475 tissue cores, contained tumor and nontumor tissues) and correlated levels of IL22BP with patient survival times.ResultsLevels of IL22BP were decreased in human colorectal tumors, compared with nontumor tissues, and correlated with levels of lymphotoxin. LTBR signaling was required for expression of IL22BP in colon tissues of mice. Wild-type mice given LTBR inhibitors had an increased tumor burden in both models, but LTBR inhibitors did not increase tumor growth in Il22bp–/– mice. Lymphotoxin directly induced expression of IL22BP in cultured human monocyte–derived dendritic cells via activation of nuclear factor κB. Reduced levels of IL22BP in colorectal tumor tissues were associated with shorter survival times of patients with CRC.ConclusionsLymphotoxin signaling regulates expression of IL22BP in colon; levels of IL22BP are reduced in human colorectal tumors, associated with shorter survival times. LTBR signaling regulates expression of IL22BP in colon tumors in mice and cultured human dendritic cells. Patients with colorectal tumors that express low levels of IL22BP might benefit from treatment with an IL22 antagonist.

Non–small cell lung cancer in never- and ever-smokers: Is it the same disease?

ObjectivesTo investigate differences in presentation, pathology, and outcomes after resection of non–small cell lung cancer (NSCLC) in never-smokers versus ever-smokers. MethodsFrom January 2006 to July 2016, 172 never-smokers and 1376 ever-smokers with NSCLC underwent pulmonary resection. The 2 cohorts were matched on patient characteristics, histopathological cancer cell type, and pathological stage group using a weighted balancing score, and overall survival and cancer recurrence were compared by pathological stage. Random forests for survival was used to identify granular cancer characteristics with different survival and cancer recurrence importance between groups. ResultsIn never-smokers, the prevalence of NSCLC was more frequent in women than in men (63% [n = 109] vs 45% [n = 63]). Compared with ever-smokers, never-smokers had less upper-lobe disease (53% [n = 91] vs 62% [n = 855]) and more adenocarcinoma (88% [n = 151] vs 62% [n = 845]). Postoperative complications were similar. Never-smokers had a lower prevalence of non–lung cancer deaths than ever-smokers (13% vs 23% at 5 years; P = .006). Among matched pairs, never-smokers had better overall survival at 5 years in pathological stage I (96% vs 78%), but worse survival in stage II (54% vs 78%). Tumor size, N category, and histopathological cell type were more important drivers of mortality and cancer recurrence in never-smokers than in ever-smokers. ConclusionsNSCLC in never-smokers affects women more than men and presents with different anatomic and histopathological distributions. Matched never-smokers have better or equivalent outcomes than ever-smokers in pathological stage I cancer, but are less likely to survive and to be cured of cancer as tumor burden increases. These findings suggest that there might be unique tumor or host behaviors differentially impacting survival of never- and ever-smoking patients with NSCLC.

Increased tumour burden alters skeletal muscle properties in the KPC mouse model of pancreatic cancer.

Cancer cachexia is a multifactorial wasting syndrome that is characterized by the loss of skeletal muscle mass and weakness, which compromises physical function, reduces quality of life, and ultimately can lead to mortality. Experimental models of cancer cachexia have recapitulated this skeletal muscle atrophy and consequent decline in muscle force generating capacity. We address these issues in a novel transgenic mouse model Kras, Trp53 and Pdx-1-Cre (KPC) of pancreatic ductal adenocarcinoma (PDA) using multi-parametric magnetic resonance (mp-MR) measures. KPC mice (n = 10) were divided equally into two groups (n = 5/group) depending on the size of the tumor i.e. tumor size <250 mm3 and >250 mm3. Using mp-MR measures, we demonstrated the changes in the gastrocnemius muscle at the microstructural level. In addition, we evaluated skeletal muscle contractile function in KPC mice using an in vivo approach. Increase in tumor size resulted in decrease in gastrocnemius maximum cross sectional area, decrease in T2 relaxation time, increase in magnetization transfer ratio, decrease in mean diffusivity, and decrease in radial diffusivity of water across the muscle fibers. Finally, we detected significant decrease in absolute and specific force production of gastrocnemius muscle with increase in tumor size. Our findings indicate that increase in tumor size may cause alterations in structural and functional parameters of skeletal muscles and that MR parameters may be used as sensitive biomarkers to noninvasively detect structural changes in cachectic muscles.

Abstract PHA04: A new somatic engineering-based model of small-cell lung cancer development

Abstract Defining the cancer genome is essential for understanding the pathogenesis, but it remains challenging due to the paucity of robust models for characterizing recurrent mutations found in cancer. To understand the molecular mechanisms underlying the development of small-cell lung cancer (SCLC), an aggressive type of lung cancer initiated by inactivation of both RB and P53, it is important to determine the functional impact of recurrent mutations found in the patient tumors. To this end, we developed a somatic engineering approach, using a CRISPR/Cre hybrid tool that expresses guide RNA, Cas9 endonuclease, and Cre recombinase from a single adenoviral vector (Ad-target of gRNA-CRISPR/Cre). Intratracheal instillation of this recombinant virus causes mutation in a candidate tumor suppressor gene while recombining floxed alleles of Rb1, Trp53, and Rbl2 in the same epithelial cell. To determine functions of Ep300, Slit2, and Fhit, whose orthologous genes are frequently mutated in SCLC patient tumors, we infect the Rb1/Trp53/Rbl2 conditional mice with the viral vectors carrying gRNAs against these genes. The mice infected with Ad-Ep300-CRISPR/Cre or Ad-Fhit-CRISPR/Cre have higher tumor burden in the lungs than those infected with Ad-lacZ-CRISPR/Cre used as control. Although Slit2 is significantly mutated in SCLC, the mice infected with Ad-Slit2-CRISPR/Cre do not increase tumor burden relative to those with Ad-lacZ-CRISPR/Cre. These results for the first time validate the oncogenic impact of Ep300 and Fhit mutations. This study demonstrates the feasibility and robustness of a new somatic engineering-based model for characterizing candidate mutations, which will facilitate the discovery of key oncogenic drivers and pathways from the large number of novel somatic alterations in SCLC. Ongoing efforts with this new approach are focused on validation of functionally unknown mutations alone or in combinations. This abstract is also being presented as Poster A39. Citation Format: Kee-Beom Kim, Dong-Wook Kim, Kwon-Sik Park. A new somatic engineering-based model of small-cell lung cancer development [abstract]. In: Proceedings of the AACR Special Conference on the Evolving Landscape of Cancer Modeling; 2020 Mar 2-5; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2020;80(11 Suppl):Abstract nr PHA04.

Tumor response and growth rate of nivolumab treatment in advanced gastric cancer: Real-world data from a large observational/translational study, JACCRO GC-08 (deliver trial).

4527 Background: Nivolumab (Nivo) demonstrated survival benefit in previously treated gastric cancer (GC) patients (pts), with a response rate (RR) of 11% and a disease control rate (DCR) of 40% (Kang YK, et al. Lancet 2017). There are few real-world data of Nivo and its predictive markers are needed in GC. It has been demonstrated that some tumors grow rapidly after Nivo treatment, but the proportion is uncertain. Methods: DELIVER trial was a prospective, multicenter, observational/translational study which assessed pts with advanced GC treated with Nivo alone and ECOG Performance Status (PS) 0-2 (UMIN000030850). The aims were to evaluate the efficacy and safety of Nivo in real world, and to discover novel host-related immune-biomarkers (gut microbiome, genetic polymorphism, gene expression, and metabolome) using fecal and blood samples which were collected before and after Nivo treatment. The RR, DCR, progression-free survival, overall survival, and tumor growth rate (TGR) were estimated as the efficacy. The response was evaluated by first imaging based on RECIST version 1.1. The TGR was calculated as a percentage increase in tumor volume during 1 month (Champiat et al. Clin Cancer Res 2017). Results: A total of 501 pts was enrolled in this study from Mar 2018 to Aug 2019, and 487 pts were evaluable for analysis (median age 70-y, 71% male, ECOG PS0/1/2 42%/44%/14%, tub/por/sig 45%/41%/5%, 21% HER2-pos, 42% pts with ascites). The DCR was 39.2% (95%CI 34.9-43.7) in evaluable pts. In 282 pts with measurable lesions, the RR was 6.7% (95%CI 4.1-10.3) and DCR was 36.5%. Sub-analysis by patient background indicated that DCR was 41% for PS0, 42% for PS1, and 24% for PS2. In addition, the DCR was lower in pts with ascites compared to those without ascites (28.6% vs. 47.0%, p= 0.005). The TGR decreased after introduction of Nivo in 124 (56.6%) of 219 evaluable pts for TGR; however, 20.5% pts were identified as experiencing hyper-progressive disease (HPD) which was defined as a ≥2-fold increase of the TGR before and after Nivo. When defining HPD as a ≥2-fold increase of tumor growth kinetics ratio and 50% increase of tumor burden, 9.6% pts experienced it. Conclusions: The real-word data of the large observational trial showed a comparable DCR to that of clinical trial in advanced GC treated with Nivo. This trial revealed the tumor behavior and some pts who experienced rapid tumor growth after Nivo treatment in clinical practice; biomarkers for HPD and the definition should be established. Clinical trial information: UMIN000030850 .

Molecular alterations with hyperprogression in lung cancer patients treated with immune checkpoint inhibitors in a large health system.

e15082 Background: Immune checkpoint inhibitor (ICI) therapy has become a mainstay of lung cancer treatment. However, not all NSCLC patients (pts) benefit, a subset paradoxically experience accelerated tumor growth while on immunotherapy. Hyperprogression (HP) refers to accelerated tumor growth on ICI with worsening clinical status. Various molecular alterations may be associated with HP including MDM2/MDM4 amplifications, EGFR aberrations, and STK11/LKB1 mutations. Kato et al. ( http://ow.ly/2n8a30nQpZv ) showed HP in 6/6 pts with MDM2/MDM4 amplification and in 2/10 pts with EGFR alterations. Methods: Lung cancer pts treated with ICI from Jan 2017 to Jan 2019 at Aurora Health Care were reviewed after IRB approved. Pts with NSCLC histology (ICD diagnosis codes and / or manual chart review), ICI treatment, and molecular testing were identified via the real world data (RWD) integrated in the Syapse platform. Additional chart review to ascertain HP was performed, and molecular results obtained via Syapse molecular lab integrations were analyzed. Pts had various forms of real world biomarker testing including oligo NGS panels. HP is defined as: 1) time-to-treatment failure (TTF) &lt; 2 months (time from the start of treatment with ICI to ICI discontinuation for any reason, including progression, patient preference, toxicity, or death), 2) &gt; 50% increase in tumor burden by RECIST, 3) spread of the disease to a new organ between baseline and first radiologic evaluation or clinical deterioration, and 4) ECOG PS ≥2 during the first 2 months of treatment. HP &gt; = 3, Progression 1-2, non-progressor 0 criteria fulfilled.Pts with and without HP were compared using Chi-squared and Fisher Exact tests. T-tests were performed for continuous variables. Results: Out of 1536 lung cancer patients 350 (22.8%) were treated with ICI including: atezolizumab (35), durvalumab (6), nivolumab (177), pembrolizumab (145). Some pts were treated with more than one ICI. 64/350 (18.2%) pts had HP. 79/350 (22.5%) pts had progressive disease without meeting the definition of HP. Biomarker associations with HP are shown in the table. Conclusions: Only the STK11/LKB1 mutation was associated with HP (P = &lt; 0.0001) with 5 of 6 STK11 pts treated with ICI showing HP. Other potential HP biomarkers will be assessed prospectively as larger panels are utilized. [Table: see text]

Hyperprogression in cancer patients on immunotherapeutic agents.

3575 Background: Patients (pts) treated with checkpoint inhibitors (CPI) may uncommonly experience accelerated progression in their tumor burden when compared to their rate of progression prior to receiving CPI. This hyperprogression has been varyingly defined and no biomarker has yet been identified. Methods: We reviewed the database from the Tumor Response Assessment Core (TRAC) at University of Michigan to identify these patients. Hyperprogression was defined as increase in tumor burden per specific immune RECIST criteria by at least 40% from baseline on the first follow-up scan with a minimum increase of 10 mm, and at least 2 times rate of growth than observed prior to start of CPI therapy. Results: Out of 741 pts who underwent baseline and 1st follow-up assessment enrolled on 118 trials, 302 (34.4%) pts received immunotherapy alone or in combination with chemotherapy/targeted agents across 49 trials. Of them, 15 pts (5%) with 5 females (33%) and median age of 63 years (range, 44 -72) met criteria for hyperprogression. The primary cancers included lung (5), colorectal (2), renal (2), biliary (1), pancreatic (1), esophageal (1), bladder (1), small bowel (1), and melanoma (1). The median time to hyperprogression was 67 (range 42-110) days, and the mean survival was 7.9 months from trial enrollment. We did not identify any clinical factor or specific CPI therapy that associated with hyperprogression. Exploratory biomarker analysis of genomic (gene panel assay) and immune subsets of tissue microenvironment (multiplex staining) is underway. Conclusions: This is the largest cohort investigated for hyperprogression across multiple cancers in literature. The rate of hyperprogression observed is less than previously reported in literature, and physicians need to be aware of this possibility while administering CPI to their patients.

Longitudinal and personalized detection of circulating tumor DNA (ctDNA) for monitoring efficacy of atezolizumab plus bevacizumab in patients with unresectable hepatocellular carcinoma (HCC).

3531 Background: ctDNA has emerged as a promising biomarker for noninvasive monitoring of treatment response and disease progression in many tumor types. However, the clinical use of ctDNA in patients with HCC has not been established. Here, we evaluated longitudinal and personalized detection of ctDNA for monitoring the treatment response to atezolizumab (atezo) + bevacizumab (bev) in patients with unresectable HCC not previously treated with systemic therapy. Methods: A subset (n = 48) of 104 patients with HCC who enrolled in Arm A of GO30140 (NCT02715531; Phase 1b) and received atezo + bev treatment were included in this study. These patients had 10 CR, 11 PR, 12 SD and 15 PD per IRF-assessed RECIST 1.1. Serial plasma samples were collected at baseline (Cycle [C]1 Day [D]1), during treatment (C2D1, C4D1) and at disease progression. Somatic mutations in individual tumors were identified via whole exome sequencing of archival tumor tissues or fresh biopsies collected before treatment. Personalized ctDNA assays (Signatera 16-plex multiplex PCR next-generation sequencing assay) specific to each patient’s tumor mutational signatures were successfully designed for 47 of 48 patients. Results: At C1D1, a median of 25.7 ng of cell-free DNA was extracted from 2-mL plasma samples. ctDNA was detected in 45 of 47 patients (96%), with a median of 70.6 mean tumor molecules/mL of plasma (MTM/mL) and a median of 1.8% mean variant allele frequency (mean VAF) in plasma. Higher ctDNA levels detected at C1D1 appeared to be associated with increased tumor burden ( P &lt; 0.03). Dynamic changes in ctDNA levels post-treatment were associated with response at C4D1. ctDNA status changed from positive at baseline to negative in 7 of 10 CR (70%), 3 of 11 PR (27%), 1 of 11 SD (9%) and 0 of 11 PD (0%) patients. Longer PFS was observed in patients whose ctDNA became undetectable post-treatment. The median PFS in patients with ctDNA present vs cleared at C4D1 was 6.5 months and not reached, respectively (HR, 12 [1.7-93], log-rank P &lt; 0.00029). Conclusions: Our study showed that Signatera, a personalized and tumor-informed ctDNA assay, could be used as a sensitive method for detecting ctDNA in patients with unresectable HCC. More importantly, our results illustrate the promise of ctDNA as an emerging biomarker that may potentially help to monitor treatment responses and disease progression in patients with HCC.

A phase II study to evaluate the need for &gt; two doses of nivolumab + ipilimumab combination (combo) immunotherapy.

10003 Background: Standard of care nivolumab (nivo) + ipilimumab (ipi) combo immunotherapy is given for 4 doses in patients (pts) with unresectable stage III/IV melanoma. Whether 4 doses are needed is questionable as retrospective data suggest pts treated with &lt;4 doses of combo due to toxicity can have durable benefit. No prospective trials have evaluated the efficacy of intentionally giving &lt;4 doses of combo in unresectable stage III/IV melanoma. Methods: In this phase 2, multicenter clinical trial (n=60), pts with unresectable stage III/IV melanoma received 2 doses of nivo (1mg/kg) + ipi (3mg/kg) followed by a CT scan at week 6. Pts with complete (CR) or partial responses (PR) by RECIST 1.1 or stable disease without an increase in total measurable tumor burden had protocol defined early favorable anti-tumor effect (FATE) and ceased combo, transitioning to maintenance nivo. Pts without FATE at week 6 received the standard third and fourth doses of combo followed by maintenance nivo. The primary endpoint was response rate by RECIST 1.1 at week 12. Secondary endpoints included additional efficacy assessments and safety. Results: 41 pts (68%) had FATE at week 6. The best overall response rates (CR + PR) by RECIST at week 12 or any time afterwards were 48% (95% CI: 35.2-61.6%) and 53% (95% CI: 40.0-66.3%), respectively. 18%, 58%, 12%, 10% had 1, 2, 3, 4 doses of combo, respectively. With a median follow-up of 11 months, any grade treatment-related toxicity occurred in 100% (57% grade 3-4) of pts. Three pts died due to treatment-related toxicity (2 myocarditis, 1 possible adrenal insufficiency). Among the 19 pts without FATE at week 6 and not selected to de-escalate combo after dose 2, no pts ultimately responded with ongoing combo dosing. Conclusions: The first 2 doses of nivo + ipi appear to drive combo’s response efficacy and toxicity. Early radiographic imaging at week 6 may be able to identify pts who do not respond to combo dosing beyond dose 2. Randomized studies are planned to evaluate 1 dose of combo to see if efficacy is maintained with reduced toxicity. Clinical trial information: NCT03122522.