Search

Background: tobacco is the main risk factor for developing lung cancer. Yet, some heavy smokers do not develop lung cancer at advanced ages while others develop it at young ages. Here, we assess for the first time the genetic background of these clinically relevant extreme phenotypes using whole exome sequencing (WES). Methods: we performed WES of germline DNA from heavy smokers who either developed lung adenocarcinoma at an early age ( extreme cases, n=50) or did not present lung adenocarcinoma or other tumors at an advanced age (extreme controls, n=50). We selected non-synonymous variants located in exonic regions and consensus splice sites of the genes that showed significantly different allelic frequencies between both cohorts. We validated our results in all the additional extreme cases (i.e., heavy smokers who developed lung adenocarcinoma at an early age) available from The Cancer Genome Atlas (TCGA). Results: the mean age for the extreme cases and controls was respectively 49.7 and 77.5 years. Mean tobacco consumption was 43.6 and 56.8 pack-years. We identified 619 significantly different variants between both cohorts, and we validated 108 of these in extreme cases selected from TCGA. Nine validated variants, located in relevant cancer related genes, such as PARP4, HLA-A or NQO1, among others, achieved statistical significance in the False Discovery Rate test. The most significant validated variant (P=4.48x10(-5)) was located in the tumor-suppressor gene ALPK2. Conclusions: we describe genetic variants associated with extreme phenotypes of high and low risk for the development of tobacco-induced lung adenocarcinoma. Our results and our strategy may help to identify high-risk subjects and to develop new therapeutic strategies. This work was supported by the Spanish Society of Medical Oncology; Fundación SEOM and Fundación Salud 2000; and Government of Navarra. LMM research work is supported by Foundation for Applied Medical Research (FIMA), Fundación Científica de la Asociación Espanola Contra el Cáncer, Fundación Ramón Areces, and Fondo de Investigación Sanitaria-Fondo Europeo de Desarrollo Regional 'Una manera de hacer Europa' (PI19/00098).

Background Genomic alterations studies in cell-free DNA (cfDNA) have increasing clinical use in oncology. Next-generation sequencing (NGS) technology provides the most complete mutational analysis, but nowadays limited data are available related to the comparison of results reported by different platforms. Here we compare two NGS panels for cfDNA: Oncomine™ Pan-Cancer Cell-Free Assay (Thermo Fisher Scientific), suitable for clinical laboratories, and Guardant360® (GuardantHealth), with more genes targeted but only available in an outsourcing laboratory. Methods Peripheral blood was obtained from 16 advanced cancer patients in which Guardant360® (G360) was requested as part of their clinical assistance. Blood samples were sent to be analyzed with G360 panel, and an additional blood sample was drawn to obtain and analyze cfDNA with Oncomine™ Pan-Cancer (OM) panel in an Ion GeneStudio S5™ System. Results cfDNA analysis globally rendered 101 mutations. Regarding the 55/101 mutations claimed to be included by manufacturers in both panels, 17 mutations were reported only by G360, 10 only by OM and 28 by both. In those coincident cases, there was a high correlation between the variant allele fractions (VAFs) calculated with each panel (r = 0.979, p Conclusions In summary, G360 and OM can produce different mutational profile in the same sample, even in genes included in both panels, which is especially important if these mutations are potentially druggable.

Epidermal growth factor receptor (EGFR) mutational testing in advanced non-small-cell lung cancer (NSCLC) is usually performed in tumor tissue, although cfDNA (cell-free DNA) could be an alternative. We evaluated EGFR mutations in cfDNA as a complementary tool in patients, who had already known EGFR mutations in tumor tissue and were treated with either EGFR-tyrosine kinase inhibitors (TKIs) or chemotherapy. We obtained plasma samples from 21 advanced NSCLC patients with known EGFR tumor mutations, before and during therapy with EGFR-TKIs and/or chemotherapy. cfDNA was isolated and EGFR mutations were analyzed with the multiple targeted cobas EGFR Mutation Test v2. EGFR mutations were detected at baseline in cfDNA from 57% of patients. The semiquantitative index (SQI) significantly decreased from the baseline (median=11, IQR=9.5-13) to the best response (median=0, IQR=0-0, p<0.01), followed by a significant increase at progression (median=11, IQR=11-15, p<0.01) in patients treated with either EGFR-TKIs or chemotherapy. The SQI obtained with the cobas EGFR Mutation Test v2 did not correlate with the concentration in copies/mL determined by droplet digital PCR. Resistance mutation p.T790M was observed at progression in patients with either type of treatment. In conclusion, cfDNA multiple targeted EGFR mutation analysis is useful for treatment monitoring in tissue of EGFR-positive NSCLC patients independently of the drug received.

Background: Myeloid-derived suppressor cells (MDSCs) are relevant in prostate cancer microenvironment collaborating in tumor development. The main tumor marker used in this disease, prostate-specific antigen (PSA), does not provide information related to this tumor microenvironment. Cancer cells secrete exosomes carrying bioactive molecules contributing to MDSCs recruitment and induction. The aim of this study was to characterize the perioperative changes of exosomal cytokines relevant in MDSCs recruitment induced by pros- tatectomy in prostate cancer patients. Methods: Blood was drawn from 26 early-stage prostate cancer patients before and after radical prostatectomy and from 16 healthy volunteers. Serum exosomes were separated by precipitation. Cytokines related with MDSC cell recruitment and activation CCL2, CXCL2, CXCL5, CXCL8, CXCL12, MIF, S100A9 and TGF-ß were measured in serum and serum-derived exosomes using immunometric assays. Results: All cytokines were detected both in serum and exosomes, except for CXCL12, which was detected only in serum. Exosomes were enriched specially in MIF, TGF-ß and CXCL2. Presurgical MIF levels in exosomes correlated negatively with serum PSA. Also, presurgical TGF-ß decreased both in serum and exosomes as Gleason score rises. Patientś presurgical exosomes had increased CCL2, CXCL5 and TGF-ß levels than exosomes from healthy controls. These differences were not observed when cytokines were analyzed in serum, except for TGF-ß.Cytokine levels of CCL2, CXCL5 decreased in patients’ postsurgical exosomes, while TGF-ß further increased. On the contrary, S100A9 levels were lower in patientś presurgical exosomes but increased after radical prostatectomy. Conclusions: Blood exosomal content in cytokines constitute an attractive source to evaluate MDSCs immuno- modulators providing additional information related to tumor microenvironment in prostate cancer

Surrogate biomarkers of efficacy are needed for anti-PD1/PD-L1 therapy, given the existence of delayed responses and pseudo-progressions. We evaluated changes in serum IL-8 levels as a biomarker of response to anti-PD-1 blockade in melanoma and non-small-cell lung cancer (NSCLC) patients.Metastatic melanoma and NSCLC patients treated with nivolumab or pembrolizumab alone or nivolumab plus ipilimumab were studied. Serum was collected at baseline; at 2-4 weeks after the first dose; and at the time-points of response evaluation. Serum IL-8 levels were determined by sandwich ELISA. Changes in serum IL-8 levels were compared with the Wilcoxon test and their strength of association with response was assessed with the Mann-Whitney test. Accuracy of changes in IL-8 levels to predict response was estimated using receiver operation characteristics curves.Twenty-nine melanoma patients treated with nivolumab or pembrolizumab were studied. In responding patients, serum IL-8 levels significantly decreased between baseline and best response (P 0.001), and significantly increased upon progression (P = 0.004). In non-responders, IL-8 levels significantly increased between baseline and progression (P = 0.013). Early changes in serum IL-8 levels (2-4 weeks after treatment initiation) were strongly associated with response (P 0.001). These observations were validated in 19 NSCLC patients treated with nivolumab or pembrolizumab (P = 0.001), and in 15 melanoma patients treated with nivolumab plus ipilimumab (P 0.001). Early decreases in serum IL-8 levels were associated with longer overall survival in melanoma (P = 0.001) and NSCLC (P = 0.015) patients. Serum IL-8 levels also correctly reflected true response in three cancer patients presenting pseudoprogression.Changes in serum IL-8 levels could be used to monitor and predict clinical benefit from immune checkpoint blockade in melanoma and NSCLC patients.

Purpose: Interleukin-8 (IL8) is a chemokine produced by malignant cells of multiple cancer types. It exerts various functions in shaping protumoral vascularization and inflammation/immunity. We evaluated sequential levels of serum IL8 in preclinical tumor models and in patients to assess its ability to estimate tumor burden. Experimental Design: IL8 levelsweremonitored by sandwich ELISAs incultured tumor cells supernatants, tumor-xenograftedmice serum, and in samples from126 patients with cancer. Wecorrelated IL8 serumlevels with baseline tumor burden and with treatment-induced changes in tumor burden, as well as with prognosis. Results: IL8 concentrations correlated with the number of IL8-producing tumor cells in culture. In xenografted neoplasms, IL8 serum levels rapidly dropped after surgical excision, indicating an accurate correlation with tumor burden. In patients with melanoma (n = 16), renal cell carcinoma (RCC; n = 23), non-small cell lung cancer (NSCLC; n = 21), or hepatocellular carcinoma (HCC; n = 30), serum IL8 concentrations correlated with tumor burden and stage, survival (melanoma, n = 16; RCC, n = 23; HCC, n = 33), and objective responses to therapy, including those to BRAF inhibitors (melanoma, n = 16) and immunomodulatory monoclonal antibodies (melanoma, n = 8). IL8 concentrations in urine (n = 18) were mainly elevated in tumors with direct contact with the urinary tract. Conclusions: IL8 levels correlate with tumor burden in preclinical models and in patients with cancer. IL8 is a potentially useful biomarker to monitor changes in tumor burden following anticancer therapy, and has prognostic significance. Fil: Sanmamed, Miguel F.. Universidad de Navarra; España Fil: Carranza Rua, Omar. Universidad de Navarra; España Fil: Alfaro, Carlos. Universidad de Navarra; España Fil: Oñate, Carmen. Universidad de Navarra; España Fil: Martín Algarra, Salvador. Universidad de Navarra; España Fil: Perez, Guiomar. Universidad de Navarra; España Fil: Landazuri, Sara F.. Universidad de Navarra; España Fil: Gonzalez, Alvaro. Universidad de Navarra; España Fil: Gross, Stefanie. University Hospital Erlangen; Alemania Fil: Rodriguez, Inmaculada. Universidad de Navarra; España Fil: Muñoz Calleja, Cecilia. Universidad Autonoma de Madrid. Hospital Universitario de la Princesa; España Fil: Rodríguez Ruiz, María. Universidad de Navarra; España Fil: Sangro, Bruno. Universidad de Navarra; España Fil: López Picazo, José M.. Universidad de Navarra; España Fil: Rizzo, Manglio Miguel. Universidad Austral. Facultad de Ciencias Biomédicas. Laboratorio de Terapia Genética; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Mazzolini Rizzo, Guillermo Daniel. Universidad Austral. Facultad de Ciencias Biomédicas. Laboratorio de Terapia Genética; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Pascual, Juan I.. Universidad de Navarra; España Fil: Andueza, Maria Pilar. Universidad de Navarra; España Fil: Perez Gracia, Jose Luis. Universidad de Navarra; España Fil: Melero, Ignacio. Universidad de Navarra; España

1540 Background: Individual susceptibility to carcinogens may depend on the genetic background. We characterized the constitutional exome of individuals presenting extreme phenotypes of high sensitivity and resistance to develop tobacco induced LUAD, correlating the results to KRAS status. Methods: From an identification cohort (n=3,631) we selected 100 caucasian heavy smokers that either developed LUAD at early age (cancer cohort, n=50) or did not develop LUAD or other tumors at advanced age (cancer free cohort, n=50). We sequenced their germline DNA with the Agilent Human Exome Capture v5 (21,522 genes, 357,999 exons). Using logistic regression we selected the most significant variants between both cohorts and correlated them with KRAS mutation status of LUAD patients. Results: mean ages for the cancer and cancer free cohorts were 50 (range 34-55) and 78 years (72-90). Mean tobacco consumptions were 44 (range 6-72) and 55 pack-years (20-124). Median coverage was 96% at >10X; median depth was 97X. Table shows the most significant variants. rs7240666 ( ALPK2) achieved top significance (p=8.14x10-5, OR 0.18). rs78898229 ( ANKRD36C) and rs74866537 ( PTPN4) were predominantly represented in patients with KRAS+ tumors, OR: 16 (3.3-78) and 11.9 (3.3-43); and rs12426243 (CCDC41) in KRAS- tumors (OR: 13 (3-53). Conclusions: Our study characterizes for the first time the genotype of individuals presenting extreme phenotypes of high and low risk to develop tobacco-induced LUAD according to KRAS status. Our results warrants further study to assess their value to screen these clinically relevant phenotypes; and to identify mechanisms of high susceptibility and resistance to carcinogens. [Table: see text]

e19112 Background: TS is the main biological target of the antifolate Pem. Some TS Pol may confer a short survival and a poor response to antifolate-treated colo-rectal cancer pts. Whether TS genotype has an independent prognostic/predictive impact on non-Asian advanced NSCLC pts treated with Pem is unknown. Methods: Twenty-five non-Asian advanced NSCLC pts treated with Pem-based regimens (1st, 2nd or 3rd line) were included. Genomic DNA was isolated from periferal blood prior to treatment. The variable number of tandem repeat (VNTR) Pol, the G>C single nucleotide Pol (SNP) and the TS 6-bp insertion/deletion (6/6) in the 3' untranslated region (UTR) Pol were analyzed and correlated with response rate (RR), progression-free survival (PFS), overall-survival (OS) and toxicity (Tx). Results: Regarding the VNTR Pol, most of the pts showed 2R/2R or 3R/2R Pol (17 pts; 68%), and 8 pts (32%) showed 3R/3R or 3R/4R Pol. A SNP (G>C) in VNTR was observed in 18 pts (72%). The Pol found in the 3´UTR region were +6/+6 in 12 pts (48%), +6/-6 in 11 pts (44%) and -6/-6 in 2 pts (8%). In the subgroup of T3-T4 pts, there was a higher RR among those showing 3R/3R Pol than those with 2R/2R Pol (100% vs 83.8%; p=0.029). The genotype +6/+6 predicted a higher RR among active/former smokers (A/FS) compared to +6/-6 (100% vs 37.5%; p=0.026). A 3R/3R Pol followed by 2R/2R and 2R/3R Pol predicted a superior RR in pts with EGFR mutations (p=0.018). Overall, a trend towards a better PFS in pts showing 2R/2R Pol was found (p=0.076). The cohort’s median overall survival (OS) was not reached during follow-up. The most frequent Tx was grade (G)1 anemia (28%) and nausea (20%) and G2 leucopenia (40%). G3-4 anemia (4%), leucopenia (16%), neutropenia (4%), astenia (8%) and dyspnea (4%) were uncommon but more frequent in pts with 2R/2R Pol (p=0.545). Conclusions: In this cohort of NSCLC pts 3R/3R Pol among T3-T4 pts and EGFR mutant pts and +6/-6 bp among A/FS significantly predicted a higher RR to Pem and may aid in treatment selection. Tx was not significantly correlated with a specific TS genotype. These interesting preliminary data warrant further validation in larger series.