As the second most deadly cancerous disease worldwide, colorectal cancer (CRC) stands in the center of scientific interest in hope to develop novel approaches for precise diagnostics and prognosis determination. Metastatic disease remains the main cause of CRC mortality. To investigate the underlying genetic differences between CRC patients with synchronous and metachronous liver metastases, we performed whole-exome sequencing of 210 patient samples using formalin-fixed paraffin-embedded samples from primary tumors and the paired liver metastatic tissue. The analyses included types and levels of mutations and copy number variation. APC and TP53 were the most commonly mutated genes in all samples with differing frequency between primary CRC (both 50%) and its metachronous metastasis (both 64%). While MPDZ gene mutations were restricted to primary tumors that developed metachronous metastases only, mutations in VCAN, MTCL1, MDN1, SHROOM2, SPEG, and GLI2 were more prevalent in primary tumors giving rise to synchronous metastases. FBN1 mutations were unique to synchronous liver metastatic tissue. Analysis of genetic interactions revealed different associations between mutated genes in patients with tumors of different chronicity, including driver genes such as TP53, which was associated with APC in synchronous patients, while in primary tumors with metachronous metastases it co-occurs with mutations in NBPF11 and PRAMEF15, respectively. The results suggest that distinct tumor progression pathways account for different chronicity outcomes further affecting patients' survival. However, larger studies are needed incorporating transcriptomic and epigenomic data to shed further light on the mechanistic chain from mutations to downstream gene expression regulation.

The luminal subtype (estrogen receptor-positive, ER+) is the most common and the most heterogeneous type of breast carcinoma (BC) in women. During our study, we determined expression levels of all microRNAs (miRNome) in 101 ER+ BC samples and identified 25 miRNAs being associated with proliferative markers. Using comprehensive in silico analyses we prioritized CHEK1, CDC25A, and CCNE1 as candidate genes affecting the proliferation of ER+ BC, with two microRNAs from the miR-497∼195 cluster identified as their potential regulators. In a cohort of 217 patients, we found a significant association between high expression of CHEK1 and shorter relapse-free survival (RFS) in luminal BC patients treated with adjuvant chemotherapy, especially in patients with luminal A subtype. In patients treated with neoadjuvant therapy, the opposite role for RFS was observed for hsa-miR-195-5p. Subsequently, we confirmed the potency of hsa-miR-195-5p to inhibit the expression of CHEK1 in vitro. Moreover, the specific Chk1 inhibitor rabusertib (LY2603618) significantly enhanced the efficacy of doxorubicin in both ER+ and ER- cell lines. In summary, we have identified the association of a specific miRNA profile with highly proliferative luminal BCs and demonstrated the ability of hsa-miR-195-5p to inhibit CHEK1 expression in BC in vitro, underlining the importance of CHEK1 expression and its inhibition for prognosis and treatment of patients with luminal BCs.

Considering the lack of molecular background of the metastatic process in pancreatic ductal adenocarcinoma (PDAC) and the fact that the location of the metastasis may carry prognostic information and potential therapeutic opportunities, we aimed to explore genomic profiles of metastases from diverse loci and their value for the patients' therapeutic management. DNA samples from paired primary and metastatic tissue of 20 patients were microdissected and sequenced using whole exome target enrichment. Somatic genetic variability, copy number variations (CNVs), and mutational signatures were assessed for associations with clinical data of patients. KRAS (78% in primary tumors, 74% in metastases), TP53 (67%-68%), CDKN2A (28%-37%), and SMAD4 (22%-26%) were the most commonly mutated oncodrivers in primary tumors and metastases. Other frequently mutated genes were CCDC187 (50%-58%), MUC5AC (50%-53%), EPPK1 (39%-63%), SYN2 (39%-26%), MUC19 (33%-47%), MUC3A (33%-26%), DNAH12 (28%-37%), ZBED3 (22%-26%), PKHD1L1 (28%-16%), and GTPBP6 (11%-32%). Lung metastases differed from other metastatic sites (liver, stomach, and locoregional) in a higher frequency of nonsense mutations in the MH2 domain of SMAD4, oncodriver comutations, gains on chromosomes 2 and 20, CNV counts, and share of signature SBS5. Somatic alterations of KRAS in metastases (P = .041) and MUC3A in both loci (P = .041 and P = .011, respectively) and CNVs count and size in metastases (P = .024 and P = .011) associated with response to systemic chemotherapy. Patients with mutated KRAS (P = .045), high mutational load (P = .004), and frequent CNVs (P = .004) in metastatic loci had shortened survival after metastasis resection. Interestingly, the personalized treatment targetable alterations, such as microsatellite instability and mismatch repair or homologous recombination deficiencies did not differ between the primary tumors and paired metastases or between the metastases from different secondary sites and had no prognostic value. The results suggest a potential prognostic role of KRAS mutations, mutation load, and CNVs in PDAC patients after metastasectomy and encourage further molecular profiling for personalized treatment of PDAC patients with different metastasis localization.

BACKGROUND:Colorectal cancer is still the second leading cause of cancer-related deaths and thus biomarkers allowing prediction of the resistance of patients to therapy and estimating their prognosis are needed. We designed a panel of 558 genes with pharmacogenomics records related to 5-fluorouracil resistance, genes important for sensitivity to other frequently used drugs, major oncodrivers, and actionable genes. We performed a target enrichment sequencing of DNA from tumors and matched blood samples of patients, and compared the results with patient prognosis stratified by systemic adjuvant chemotherapy. RESULTS:The median number of detected variants per tumor sample was 18.5 with 4 classified as having a high predicted functional effect and 14.5 moderate effect. APC, TP53, and KRAS were the most frequent mutated genes (64%, 59%, and 42% of mutated samples, respectively) followed by FAT4 (23%), FBXW7, and PIK3CA (16% for both). Patients with advanced stage III had more frequently APC, TP53, or KRAS mutations than those in stages I or II. KRAS mutation counts followed an increasing trend with grade (G1 < G2 < G3). The response to adjuvant therapy was worse in carriers of frameshift mutations in APC or 12D variant in KRAS, but none of these oncodrivers had prognostic value. Carriage of somatic mutations in any of the genes ABCA13, ANK2, COL7A1, NAV3, or UNC80 had prognostic relevance for worse overall survival (OS) of all patients. In contrast, mutations in FLG, GLI3, or UNC80 were prognostic in the same direction for patients untreated, and mutations in COL6A3, LRP1B, NAV3, RYR1, RYR3, TCHH, or TENM4 for patients treated with adjuvant therapy. The first association was externally validated. From all germline variants with high or moderate predicted functional effects (median 326 per patient), > 5% frequency and positive Manhattan plot based on 3-year RFS, rs72753407 in NFACS, rs34621071 in ERBB4, and rs2444274 in RIF1 were significantly associated with RFS, OS or both. CONCLUSIONS:The present study identified several putative somatic and germline genetic events with prognostic potential for colorectal cancer that should undergo functional characterization.

High-grade serous ovarian carcinoma (HGSC) is the most common subtype of ovarian cancer and is among the most fatal gynecological malignancies worldwide, due to late diagnosis at advanced stages and frequent therapy resistance. In 47 HGSC patients, we assessed somatic and germline genetic variability of a custom panel of 144 known or suspected HGSC-related genes by high-coverage targeted DNA sequencing to identify the genetic determinants associated with resistance to platinum-based therapy. In the germline, the most mutated genes were DNAH14 (17%), RAD51B (17%), CFTR (13%), BRCA1 (11%), and RAD51 (11%). Somatically, the most mutated gene was TP53 (98%), followed by CSMD1/2/3 (19/19/36%), and CFTR (23%). Results were compared with those from whole exome sequencing of a similar set of 35 HGSC patients. Somatic variants in TP53 were also validated using GENIE data of 1287 HGSC samples. Our approach showed increased prevalence of high impact somatic and germline mutations, especially those affecting splice sites of TP53, compared to validation datasets. Furthermore, nonsense TP53 somatic mutations were negatively associated with patient survival. Elevated TP53 transcript levels were associated with platinum resistance and presence of TP53 missense mutations, while decreased TP53 levels were found in tumors carrying mutations with predicted high impact, which was confirmed in The Cancer Genome Atlas data (n = 260). Targeted DNA sequencing of TP53 combined with transcript quantification may contribute to the concept of precision oncology of HGSC. Future studies should explore targeting the p53 pathway based on specific mutation types and co-analyze the expression and mutational profiles of other key cancer genes.

The gut microbiota is implicated in the pathogenesis of colorectal cancer (CRC). We aimed to map the CRC mucosal microbiota and metabolome and define the influence of the tumoral microbiota on oncological outcomes. A multicentre, prospective observational study was conducted of CRC patients undergoing primary surgical resection in the UK (n = 74) and Czech Republic (n = 61). Analysis was performed using metataxonomics, ultra-performance liquid chromatography-mass spectrometry (UPLC-MS), targeted bacterial qPCR and tumour exome sequencing. Hierarchical clustering accounting for clinical and oncological covariates was performed to identify clusters of bacteria and metabolites linked to CRC. Cox proportional hazards regression was used to ascertain clusters associated with disease-free survival over median follow-up of 50 months. Thirteen mucosal microbiota clusters were identified, of which five were significantly different between tumour and paired normal mucosa. Cluster 7, containing the pathobionts Fusobacterium nucleatum and Granulicatella adiacens, was strongly associated with CRC (PFDR = 0.0002). Additionally, tumoral dominance of cluster 7 independently predicted favourable disease-free survival (adjusted p = 0.031). Cluster 1, containing Faecalibacterium prausnitzii and Ruminococcus gnavus, was negatively associated with cancer (PFDR = 0.0009), and abundance was independently predictive of worse disease-free survival (adjusted p = 0.0009). UPLC-MS analysis revealed two major metabolic (Met) clusters. Met 1, composed of medium chain (MCFA), long-chain (LCFA) and very long-chain (VLCFA) fatty acid species, ceramides and lysophospholipids, was negatively associated with CRC (PFDR = 2.61 × 10−11); Met 2, composed of phosphatidylcholine species, nucleosides and amino acids, was strongly associated with CRC (PFDR = 1.30 × 10−12), but metabolite clusters were not associated with disease-free survival (p = 0.358). An association was identified between Met 1 and DNA mismatch-repair deficiency (p = 0.005). FBXW7 mutations were only found in cancers predominant in microbiota cluster 7. Networks of pathobionts in the tumour mucosal niche are associated with tumour mutation and metabolic subtypes and predict favourable outcome following CRC resection.

PURPOSE Analysis of somatic variant profiles in retrospectively collected pairs of primary tumors and synchronous liver metastases from surgically treated patients with colorectal carcinomas. Mutational profiles were compared between groups of patients stratified by response to chemotherapy and survival. PATIENTS AND METHODS The study used whole-exome sequencing of tumor sample pairs from 20 patients diagnosed and treated at a single center. The Cancer Genome Atlas COAD-READ data set (n = 380) was used for validation in silico, where possible. RESULTS The most frequently altered oncodrivers were APC (55% in primaries and 60% in metastases), TP53 (50/45), TRIP11 (30/5), FAT4 (20/25), and KRAS (15/25). Harboring variants with a high or moderate predicted functional effect in KRAS in primary tumors was significantly associated with poor relapse-free survival in both our sample set and the validation data set. We found a number of additional prognostic associations, including mutational load, alterations in individual genes, oncodriver pathways, and single base substitution (SBS) signatures in primary tissues, which were not confirmed by validation. Altered ATM, DNAH11, and MUC5AC, or a higher share of SBS24 signature in metastases seemed to represent poor prognostic factors, but because of a lack of suitable validation data sets, these results must be treated with extreme caution. No gene or profile was significantly associated with response to chemotherapy. CONCLUSION Taken together, we report subtle differences in exome mutational profiles between paired primary tumors and synchronous liver metastases and a distinct prognostic relevance of KRAS in primary tumors. Although the general scarcity of primary tumor-synchronous metastasis sample pairs with high-quality clinical data makes robust validation difficult, this study provides potentially valuable data for utilization in precision oncology and could serve as a springboard for larger studies.

The chemotherapeutic efficacy in colorectal cancer (CRC) is limited due to the inter-individual variability in drug response and the development of tumour resistance. ATP-binding cassette (ABC) transporters are crucial in the development of resistance by the efflux of anticancer agents from cancer cells. In this study, we identified 14 single nucleotide polymorphisms (SNPs) in 11 ABC transporter genes acting as an expression of quantitative trait loci (eQTLs), i.e. whose variation influence the expression of many downstream genes. These SNPs were genotyped in a case-control study comprising 1098 cases and 1442 healthy controls and analysed in relation to CRC development risk and patient survival. Considering a strict correction for multiple tests, we did not observe any significant association between SNPs and CRC risk. The rs3819720 polymorphism in the ABCB3/TAP2 gene was statistically significantly associated with shorter overall survival (OS) in the codominant, and dominant models [GA vs. GG, hazard ratio (HR) = 1.48; P = 0.002; AA vs. GG, HR = 1.70; P = 0.004 and GA + AA vs. GG, HR = 1.52; P = 0.0006]. Additionally, GA carriers of the same SNP displayed worse OS after receiving 5-FU based chemotherapy. The variant allele of rs3819720 polymorphism statistically significantly affected the expression of 36 downstream genes. Screening for eQTL polymorphisms in relevant genes such as ABC transporters that can regulate the expression of several other genes may help to identify the genetic background involved in the individual response to the treatment of CRC patients.

Decellularized scaffolds can serve as an excellent three-dimensional environment for cell repopulation. They maintain tissue-specific microarchitecture of extracellular matrix proteins with important spatial cues for cell adhesion, migration, growth, and differentiation. However, criteria for quality assessment of the three-dimensional structure of decellularized scaffolds are rather fragmented, usually study-specific, and mostly semi-quantitative. Thus, we aimed to develop a robust structural assessment system for decellularized porcine liver scaffolds. Five scaffolds of different quality were used to establish the new evaluation system. We combined conventional semi-quantitative scoring criteria with a quantitative scaffold evaluation based on automated image analysis. For the quantitation, we developed a specific open source software tool (ScaffAn) applying algorithms designed for texture analysis, segmentation, and skeletonization. ScaffAn calculates selected parameters characterizing structural features of porcine liver scaffolds such as the sinusoidal network. After evaluating individual scaffolds, the total scores predicted scaffold interaction with cells in terms of cell adhesion. Higher scores corresponded to higher numbers of cells attached to the scaffolds. Moreover, our analysis revealed that the conventional system could not identify fine differences between good quality scaffolds while the additional use of ScaffAn allowed discrimination. This led us to the conclusion that only using the combined score resulted in the best discrimination between different quality scaffolds. Overall, our newly defined evaluation system has the potential to select the liver scaffolds most suitable for recellularization, and can represent a step toward better success in liver tissue engineering.

One of the principal mechanisms of chemotherapy resistance in highly frequent solid tumors, such as colorectal cancer (CRC), is the decreased activity of drug transport into tumor cells due to low expression of important membrane proteins, such as solute carrier (SLC) transporters. Sequence complementarity is a major determinant for target gene recognition by microRNAs (miRNAs). Single-nucleotide polymorphisms (SNPs) in target sequences transcribed into messenger RNA may therefore alter miRNA binding to these regions by either creating a new site or destroying an existing one. miRSNPs may explain the modulation of expression levels in association with increased/decreased susceptibility to common diseases as well as in chemoresistance and the consequent inter-individual variability in drug response. In the present study, we investigated whether miRSNPs in SLC transporter genes may modulate CRC susceptibility and patient's survival. Using an in silico approach for functional predictions, we analyzed 26 miRSNPs in 9 SLC genes in a cohort of 1368 CRC cases and 698 controls from the Czech Republic. After correcting for multiple tests, we found several miRSNPs significantly associated with patient's survival. SNPs in SLCO3A1, SLC22A2 and SLC22A3 genes were defined as prognostic factors in the classification and regression tree analysis. In contrast, we did not observe any significant association between miRSNPs and CRC risk. To the best of our knowledge, this is the first study investigating miRSNPs potentially affecting miRNA binding to SLC transporter genes and their impact on CRC susceptibility or patient's prognosis.

Introduction The colorectal cancer (CRC) microbiome is niche specific and individualised. Several putative driver organisms enriched on CRCs have been identified from human studies, but few data exist which properly account for important clinical variables in CRC. In this study, we used a meta-taxonomic approach to demonstrate how the CRC microbiome varies with disease stage, histological markers of prognosis and host molecular phenotypes. Method A prospective study was performed on patients undergoing colonoscopy and elective surgery for CRC at three hospitals in UK and Czech Republic. Tissue was sampled from tumours, adenomas, adjacent normal mucosa and mucosa from healthy colon controls. The V1-2 regions of the 16S rRNA gene were sequenced (Illumina MiSeq); data were processed in Mothur and analysed in Stamp and R. Species assignment was performed with NCBI BLAST for microbial genomes. False discovery rate p value correction accounted for multiple testing. Histological analysis and tumour molecular phenotyping were performed according to Royal College of Pathology guidelines. Results One hundred and ninety six patients were recruited: 158 CRC patients, 24 adenoma patients and 14 normal colon controls (median age 70; range 35–90). Tumours were staged as 6 T0, 4 T1, 23 T2, 97 T3, 27 T4; 99 N0, 40 N1, 27 N2; 6 M1. No significant differences were seen in diversity or taxonomy between the UK and Czech cohorts. Adenoma and healthy colon control samples were taxonomically indistinct. However, CRCs were characterised by reduced Shannon diversity (p<0.01), with enrichment of organisms including Bacteroides fragilis,Fusobacterium nucleatum and under-representation of Bacteroides vulgatus,Bacteroides uniformisandFaecalibacterium prausnitzii (all q<0.01). Furthermore, we found a significant progressive reduction in the expression of Bacteroides vulgatus with advancing T stage and a corresponding increase in Fusobacterium nucleatum expression (figure). Additionaly, samples from patients with T4 tumours and cancers expressing histological and molecular markers of poor prognosis were characterised by enrichment of certain low abundance oral pathobionts: Parvimonas micra,Porphyromonas gingivalis and Prevotella spp. Conclusion This large prospective analysis demonstrates that the CRC microbiome is stage-specific and appears to evolve with disease progression. We conclude that oral pathobionts which colonise advanced stage disease relate to markers of tumour prognosis, raising the possibility that they may be directly influencing tumour invasion. Disclosure of Interest None Declared Abstract OC-061 Figure 1 Progressive change in relative abundance of Bacteroides Vulgatus (left) and Fusobacterium Nucleatum (right) against T stage (A: Adenoma).

Purpose/Background: There is growing evidence that the gut microbiome modulates patient response to chemotherapy and radiotherapy. However, it is unclear how these therapies modify anatomically discrete regions of mucosal ecology during therapy. We therefore applied a 16S rRNA gene sequencing approach to study the meta-taxonomy of the mucosal microbiome in patients undergoing neoadjuvant therapy for rectal cancer.Methods/Interventions: A prospective, observational multi-centred study was performed in patients undergoing elective surgery for colorectal tumors at three teaching hospitals in London, UK and Pilsen, Czech Republic. All patients received bowel preparation prior to surgery. Clinical meta data on therapy was prospectively collected. Tissue from on tumor, and from normal mucosa at 10cms were sampled and snap frozen at-80 C. DNA was extracted from mucosal samples using the PowerLyzer PowerSoil DNA Isolation Kit (MO BIO) and the V1-2 regions of the 16S rRNA gene sequences were sequenced on the Illumina MiSeq platform. Data were analysed by Mothur to determine OTU abundance per sample and were further analysed in Stamp and R.Results/Outcome (s): 49 patients with rectal cancer were recruited (28 men, 21 women; median age 68, range 35-86). Cancers were staged as 1 T1, 13 T2, 27 T3 & 8 T4; 27 N0, 12 N1, 8 N2; 47 M0, 2 M1. 22 patients received neo-adjuvant treatment (9 combined chemoradiotherapy, 5 chemotherapy alone, 8 radiotherapy alone). Chemotherapy included FOLFOX (five patients), 5-fluoruracil alone (two patients) and capecitabine (six patients). Inter-individual variation in gut …

This study addresses involvement of major 5-fluorouracil (5-FU) pathway genes in the prognosis of colorectal carcinoma patients.

This study investigated the prognostic importance of protein expression of ATP-binding cassette (ABC) transporters ABCC10 and ABCC11 in colorectal cancer.

The question of susceptibility to squamous cell carcinoma of head and neck (SCCHN) in the environmental context was addressed by analysis of functional polymorphisms in enzymes metabolizing smoke constituents and/or alcohol (CYP2A 13, CYP1B1, EPHX1, NQO1, GSTM1, GSTP1, GSTT1, ADH1B and ADH1C). Case-control study of 122 age- and sex-matched pairs of subjects was performed using so far unexplored Central European Slavic population with high level of tobacco and alcohol abuse.Age-, gender-, smoking- and alcohol-adjusted logistic regression failed to demonstrate any significant association of the analyzed polymorphisms with the SCCHN risk. When interactions between potential modifiers of effect, i.e. smoking and alcohol were tested, drinkers seemed to be at lower risk than nondrinkers when carrying the heterozygous genotype Ile/Val in codon 432 of CYP1B1 (OR=0.42; 95% CI=0.21-0.83; p=0.013 vs. OR=1.02; 95% CI=0.34-2.94; p=0.977). Similarly, drinkers were at lower risk than nondrinkers when carrying the heterozygous genotype Pro/Ser in codon 187 of NQO1 (OR=0.41; 95% CI=0.19-0.88; p=0.022 vs. OR=0.96; 95% CI=0.29-3.12; p=0.948). More interestingly, drinkers carrying the rare homozygous genotype Val/Val in codon 350 of ADH1C were at significantly higher risk than nondrinkers carrying this genotype (OR=4.01; 95% CI=1.61-10.01; p=0.003 vs. OR=0.93; 95% CI=0.25-3.57; p=0.919). This result confirmed findings of previously published studies. Smoking did not significantly modify the effect of genotypes.Our data thus demonstrate that genetic susceptibility to SCCHN shall be further followed on populations with different genetic background and lifestyle.