Investigating the feasibility of tumour molecular profiling in gastrointestinal malignancies in routine clinical practice.

Background: Targeted capture sequencing can potentially facilitate precision medicine, but the feasibility of this approach in gastrointestinal (GI) malignancies is unknown. Patients and methods: The FOrMAT (Feasibility of a Molecular Characterisation Approach to Treatment) study was a feasibility study enrolling patients with advanced GI malignancies from February 2014 to November 2015. Targeted capture sequencing (mainly using archival formalin-fixed paraffin-embedded diagnostic/resection samples) was carried out to detect mutations, copy number variations and translocations in up to 46 genes which had prognostic/predictive significance or were targets in current/upcoming clinical trials. Results: Of the 222 patients recruited, 215 patients (96.8%) had available tissue samples, 125 patients (56.3%) had ≥16 genes successfully sequenced and 136 patients (61.2%) had ≥1 genes successfully sequenced. Sample characteristics influenced the proportion of successfully sequenced samples, e.g. tumour type (colorectal 70.9%, biliary 52.6%, oesophagogastric 50.7%, pancreas 27.3%, P = 0.002), tumour cellularity (high versus low: 78.3% versus 13.3%, P ≤ 0.001), tumour content (high versus low: 78.6% versus 27.3%, P = 0.001) and type of sample (resection versus biopsy: 82.4% versus 47.6%, P ≤ 0.001). Currently, actionable alterations were detected in 90 (40.5%) of the 222 patients recruited (66% of the 136 patients sequenced) and 2 patients subsequently received a targeted therapy. The most frequently detected currently actionable alterations were mutations in KRAS, BRAF, TP53 and PIK3CA. For the 205 patients with archival samples, the median time to obtain sequencing results was 18.9 weeks, including a median of 4.9 weeks for sample retrieval and 5.1 weeks for sequencing. Conclusions: Targeted sequencing detected actionable alterations in formalin-fixed paraffin-embedded samples, but tissue characteristics are of critical importance in determining sequencing success. Routine molecular profiling of GI tumours outside of clinical trials is not an effective use of healthcare resources unless more targeted drugs become available. ClinicalTrials.gov identifier: NCT02112357.

Carbon dating cancer: defining the chronology of metastatic progression in colorectal cancer.

Background: Patients often ask oncologists how long a cancer has been present before causing symptoms or spreading to other organs. The evolutionary trajectory of cancers can be defined using phylogenetic approaches but lack of chronological references makes dating the exact onset of tumours very challenging. Patients and methods: Here, we describe the case of a colorectal cancer (CRC) patient presenting with synchronous lung metastasis and metachronous thyroid, chest wall and urinary tract metastases over the course of 5 years. The chest wall metastasis was caused by needle tract seeding, implying a known time of onset. Using whole genome sequencing data from primary and metastatic sites we inferred the complete chronology of the cancer by exploiting the time of needle tract seeding as an in vivo 'stopwatch'. This approach allowed us to follow the progression of the disease back in time, dating each ancestral node of the phylogenetic tree in the past history of the tumour. We used a Bayesian phylogenomic approach, which accounts for possible dynamic changes in mutational rate, to reconstruct the phylogenetic tree and effectively 'carbon date' the malignant progression. Results: The primary colon cancer emerged between 5 and 8 years before the clinical diagnosis. The primary tumour metastasized to the lung and the thyroid within a year from its onset. The thyroid lesion presented as a tumour-to-tumour deposit within a benign Hurthle adenoma. Despite rapid metastatic progression from the primary tumour, the patient showed an indolent disease course. Primary cancer and metastases were microsatellite stable and displayed low chromosomal instability. Neo-antigen analysis suggested minimal immunogenicity. Conclusion: Our data provide the first in vivo experimental evidence documenting the timing of metastatic progression in CRC and suggest that genomic instability might be more important than the metastatic potential of the primary cancer in dictating CRC fate.

Prognostic role of the LCS6 KRAS variant in locally advanced rectal cancer: results of the EXPERT-C trial.

BACKGROUND: Lethal-7 (let-7) is a tumour suppressor miRNA which acts by down-regulating several oncogenes including KRAS. A single-nucleotide polymorphism (rs61764370, T > G base substitution) in the let-7 complementary site 6 (LCS-6) of KRAS mRNA has been shown to predict prognosis in early-stage colorectal cancer (CRC) and benefit from anti-epidermal growth factor receptor monoclonal antibodies in metastatic CRC. PATIENTS AND METHODS: We analysed rs61764370 in EXPERT-C, a randomised phase II trial of neoadjuvant CAPOX followed by chemoradiotherapy, surgery and adjuvant CAPOX plus or minus cetuximab in locally advanced rectal cancer. DNA was isolated from formalin-fixed paraffin-embedded tumour tissue and genotyped using a PCR-based commercially available assay. Kaplan-Meier method and Cox regression analysis were used to calculate survival estimates and compare treatment arms. RESULTS: A total of 155/164 (94.5%) patients were successfully analysed, of whom 123 (79.4%) and 32 (20.6%) had the LCS-6 TT and LCS-6 TG genotype, respectively. Carriers of the G allele were found to have a statistically significantly higher rate of complete response (CR) after neoadjuvant therapy (28.1% versus 10.6%; P = 0.020) and a trend for better 5-year progression-free survival (PFS) [77.4% versus 64.5%: hazard ratio (HR) 0.56; P = 0.152] and overall survival (OS) rates (80.3% versus 71.9%: HR 0.59; P = 0.234). Both CR and survival outcomes were independent of the use of cetuximab. The negative prognostic effect associated with KRAS mutation appeared to be stronger in patients with the LCS-6 TT genotype (HR PFS 1.70, P = 0.078; HR OS 1.79, P = 0.082) compared with those with the LCS-6 TG genotype (HR PFS 1.33, P = 0.713; HR OS 1.01, P = 0.995). CONCLUSION: This analysis suggests that rs61764370 may be a biomarker of response to neoadjuvant treatment and an indicator of favourable outcome in locally advanced rectal cancer possibly by mitigating the poor prognosis of KRAS mutation. In this setting, however, this polymorphism does not appear to predict cetuximab benefit.

HER2 in high-risk rectal cancer patients treated in EXPERT-C, a randomized phase II trial of neoadjuvant capecitabine and oxaliplatin (CAPOX) and chemoradiotherapy (CRT) with or without cetuximab.

BACKGROUND: HER2 is an established therapeutic target in breast and gastric cancers. The role of HER2 in rectal cancer is unclear, as conflicting data on the prevalence of HER2 expression in this disease have been reported. We evaluated the prevalence of HER2 and its impact on the outcome of high-risk rectal cancer patients treated with neoadjuvant CAPOX and CRT±cetuximab in the EXPERT-C trial. PATIENTS AND METHODS: Eligible patients with available tumour tissue for HER2 analysis were included. HER2 expression was determined by immunohistochemistry (IHC) in pre-treatment biopsies and/or surgical specimens (score 0-3+). Immunostaining was scored according to the consensus panel recommendations on HER2 scoring for gastric cancer. Tumours with equivocal IHC result (2+) were tested for HER2 amplification by D-ISH. Tumours with IHC 3+ or D-ISH ratio ≥2.0 were classified as HER2+. The impact of HER2 on primary and secondary end points of the study was analysed. RESULTS: Of 164 eligible study patients, 104 (63%) biopsy and 114 (69%) surgical specimens were available for analysis. Only 3 of 104 (2.9%) and 3 of 114 (2.6%) were HER2+, respectively. In 77 patients with paired specimens, concordance for HER2 status was found in 74 (96%). Overall, 141 patients were assessable for HER2 and 6 out of 141 (4.3%) had HER2 overexpression and/or amplification. The median follow-up was 58.6 months. HER2 was not associated with a difference in the outcome for any of the study end points, including in the subset of 90 KRAS/BRAF wild-type patients treated±cetuximab. CONCLUSIONS: Based on the low prevalence of expression as recorded in the EXPERT-C trial, HER2 does not appear to represent a useful therapeutic target in high-risk rectal cancer. However, the role of HER2 as a potential predictive biomarker of resistance to anti-EGFR-based treatments and a therapeutic target in anti-EGFR refractory metastatic colorectal cancer (CRC) warrants further investigation. TRIAL REGISTRATION: ISRCTN Register: 99828560.

Biomarker analysis in oesophagogastric cancer: Results from the REAL3 and TransMAGIC trials.

BACKGROUND: REAL3 (Randomised ECF for Advanced or Locally advanced oesophagogastric cancer 3) was a phase II/III trial designed to evaluate the addition of panitumumab (P) to epirubicin, oxaliplatin and capecitabine (EOC) in untreated advanced oesophagogastric adenocarcinoma, or undifferentiated carcinoma. MAGIC (MRC Adjuvant Gastric Infusional Chemotherapy) was a phase III study which demonstrated that peri-operative epirubicin, cisplatin and infused 5-fluorouracil (ECF) improved survival in early oesophagogastric adenocarcinoma. PATIENTS AND METHODS: Analysis of response rate (RR; the primary end-point of phase II) and biomarkers in the first 200 patients randomised to EOC or modified dose (m) EOC+P in REAL3 was pre-planned to determine if molecular selection for the on-going study was indicated. KRAS, BRAF and PIK3CA mutations and PTEN expression were assessed in pre-treatment biopsies and results correlated with response to mEOC+P. Association between these biomarkers and overall survival (OS) was assessed in MAGIC patients to determine any prognostic effect. RESULTS: RR was 52% to mEOC+P, 48% to EOC. Results from 175 assessable biopsies: mutations in KRAS (5.7%), BRAF (0%), PIK3CA (2.5%) and loss of PTEN expression (15.0%). None of the biomarkers evaluated predicted resistance to mEOC+P. In MAGIC, mutations in KRAS, BRAF and PIK3CA and loss of PTEN (phosphatase and tensin homolog) were found in 6.3%, 1.0%, 5.0% and 10.9%, respectively, and were not associated with survival. CONCLUSIONS: The RR of 52% in REAL3 with mEOC+P met pre-defined criteria to continue accrual to phase III. The frequency of the mutations was too low to exclude any prognostic or predictive effect.

Effect of HER2 on prognosis and benefit from peri-operative chemotherapy in early oesophago-gastric adenocarcinoma in the MAGIC trial.

BACKGROUND: Perioperative epirubicin, cisplatin and fluorouracil (ECF) chemotherapy improves survival in operable oesophago-gastric cancer [Adjuvant Gastric Cancer Infusional Chemotherapy (MAGIC) trial HR 0.75 (0.6-0.93)]. HER2 amplification is reported to predict enhanced benefit from anthracyclines in breast cancer. We sought to define whether HER2 predicts benefit from ECF in oesophago-gastric cancer. PATIENTS AND METHODS: Diagnostic biopsies and/or resection specimens were collected from 415 of 503 MAGIC trial patients (82.5%). HER2 was evaluated by immunohistochemistry (IHC) and brightfield dual in situ hybridisation (BDISH) in tissue microarrays. The prognostic and predictive impact of HER2 status was investigated. RESULTS: Concordance between HER2 over-expression (IHC3+) and amplification was 96%. Results of HER2 assessment in biopsy and resection specimens were concordant in 92.9% (145/156). HER2 positive rate (IHC3+, or IHC2+/BDISH positive) was 10.9% in the whole cohort and 10.4% in resection specimens. A further 4.0% of resections were IHC negative/BDISH positive. HER2 status was neither prognostic, nor (in pre-treatment biopsies) predicted enhanced benefit from chemotherapy [HER2 positive HR 0.74 (0.14-3.77); HER2 negative HR 0.58 (0.41-0.82), interaction P = 0.7]. However, the power of the predictive analysis was limited by the small number of HER2 positive pre-treatment biopsies. CONCLUSIONS: HER2 status is not an independent prognostic biomarker in early oesophago-gastric adenocarcinoma.

Inducible nitric oxide synthase (iNOS) and nitric oxide (NO) are important mediators of reflux-induced cell signalling in esophageal cells.

Nitric oxide (NO) produced by inducible nitric oxide synthase (iNOS) has been implicated in both DNA damage induction and aberrant cell signalling in various tissue and cell backgrounds. We investigated here the role of iNOS and NO in DNA damage induction and nuclear factor-kappa B (NF-κB) signalling in esophageal cells in vitro. As esophageal adenocarcinoma develops in a background of Barrett's esophagus secondary to reflux disease, it is possible that inflammatory mediators like NO may be important in esophageal cancer development. We show that reflux components like stomach acid and bile acids [deoxycholic acid (DCA)] can induce iNOS gene and protein expression and produce NO generation in esophageal cells, using real-time PCR, western blotting and NO sensitive fluorescent probes, respectively. This up-regulation of iNOS expression was not dependent on NF-κB activity. DCA-induced DNA damage was independent of NF-κB and only partially dependent on iNOS and NO, as measured by the micronucleus assay. These same reflux constituents also activated the oncogenic transcription factor NF-κB, as measured by transcription factor enzyme-linked immunosorbent assay and gene expression studies with NF-κB linked genes (e.g. interleukin-8). Importantly, we show here for the first time that basal levels of NF-κB activity (and possibly acid and DCA-induced NF-κB) are dependent on iNOS/NO and this may lead to a positive feedback loop whereby induced iNOS is upstream of NF-κB, hence prolonging and potentially amplifying this signalling, presumably through NO activation of NF-κB. Furthermore, we confirm increased protein levels of iNOS in esophageal adenocarcinoma and, therefore, in neoplastic development in the esophagus.

Curcumin abrogates bile-induced NF-κB activity and DNA damage in vitro and suppresses NF-κB activity whilst promoting apoptosis in vivo, suggesting chemopreventative potential in Barrett's oesophagus.

INTRODUCTION: Curcumin has been suggested to possess anti-neoplastic properties. As oesophageal adenocarcinoma (OA) and Barrett's oesophagus (BO) represent a neoplastic series, we postulated that curcumin supplementation may slow neoplastic progression at this site. Our aim was to investigate the effects of curcumin in vitro and in vivo on markers of oesophageal cancer progression. METHODS: We investigated the in vitro ability of curcumin to prevent bile acid-induced DNA damage using micronucleus assay and nuclear factor-kappaB (NF-κB) activity in the oesophageal cell lines (OE33) using real-time PCR of the extracted RNA. We also analysed NF-κB p65 activation in curcumin-pre-treated OE33 cells exposed to deoxycholic acid (DCA) using ELISA. In another pilot study, BO patients took a daily 500 mg curcumin tablet for 7 days prior to their endoscopy. In biopsies collected from these patients (n=33, 16 curcumin, 17 control), we examined NF-κB-driven gene expression (interleukin (IL)-8, inhibitor- kappaB (I-κB)) using real-time PCR of the extracted RNA from the biopsy sample. The apoptotic frequency was assessed by counting the number of apoptotic bodies in the epithelial cells from the Barrett's tissue with and without curcumin. RESULTS: In vitro, curcumin (50 µM) significantly abrogated DNA damage and NF-κB activity induced by bile. Pretreating OE33 cells with curcumin (50 µM) completely abolished the ability of DCA (300 µM) to activate NF-κB. In vivo, IL-8 expression was non-significantly suppressed in the curcumin-supplemented patients compared to the squamous control tissue, whilst also showing a doubling in the apoptotic frequency compared to non-supplemented control patients. CONCLUSIONS: Curcumin abrogated bile-driven effects in vitro. The in vivo data also suggests that curcumin supplementation had beneficial effects (increased apoptosis, potentially reduced NF-κB activity) in the Barrett's tissues themselves, despite poor delivery of the curcumin to the oesophagus.

Curcumin abrogates bile-induced NF-kB activity and DNA damage in vitro and suppresses NF-kB activity whilst promoting apoptosis in vivo, suggesting chemopreventative potential in Barrett's oesophagus

INTRODUCTION: Curcumin has been suggested to possess anti-neoplastic properties. As oesophageal adenocarcinoma (OA) and Barrett's oesophagus (BO) represent a neoplastic series, we postulated that curcumin supplementation may slow neoplastic progression at this site. Our aim was to investigate the effects of curcumin in vitro and in vivo on markers of oesophageal cancer progression. METHODS: We investigated the in vitro ability of curcumin to prevent bile acid-induced DNA damage using micronucleus assay and nuclear factor-kappaB (NF-κB) activity in the oesophageal cell lines (OE33) using real-time PCR of the extracted RNA. We also analysed NF-κB p65 activation in curcumin-pre-treated OE33 cells exposed to deoxycholic acid (DCA) using ELISA. In another pilot study, BO patients took a daily 500 mg curcumin tablet for 7 days prior to their endoscopy. In biopsies collected from these patients (n=33, 16 curcumin, 17 control), we examined NF-κB-driven gene expression (interleukin (IL)-8, inhibitor- kappaB (I-κB)) using real-time PCR of the extracted RNA from the biopsy sample. The apoptotic frequency was assessed by counting the number of apoptotic bodies in the epithelial cells from the Barrett's tissue with and without curcumin. RESULTS: In vitro, curcumin (50 μM) significantly abrogated DNA damage and NF-κB activity induced by bile. Pretreating OE33 cells with curcumin (50 μM) completely abolished the ability of DCA (300 μM) to activate NF-κB. In vivo, IL-8 expression was non-significantly suppressed in the curcumin-supplemented patients compared to the squamous control tissue, whilst also showing a doubling in the apoptotic frequency compared to non-supplemented control patients. CONCLUSIONS: Curcumin abrogated bile-driven effects in vitro. The in vivo data also suggests that curcumin supplementation had beneficial effects (increased apoptosis, potentially reduced NF-κB activity) in the Barrett's tissues themselves, despite poor delivery of the curcumin to the oesophagus (AU)

The bile acid deoxycholic acid has a non-linear dose response for DNA damage and possibly NF-kappaB activation in oesophageal cells, with a mechanism of action involving ROS.

Deoxycholic acid (DCA) is a secondary bile acid implicated in various cancers of the gastrointestinal (GI) tract. In oesophageal adenocarcinoma, DCA is believed to contribute to carcinogenesis during reflux where stomach contents enter the lower oesophagus. It is imperative that we understand the mechanisms whereby oesophageal carcinogens function in order that therapeutic options may be developed. We have previously shown that DCA can damage chromosomes and does so through its generation of reactive oxygen species (ROS). We show here, after detailed experiments, that DCA appears to have a non-linear dose response for DNA damage. DCA induces DNA damage (as measured by the micronucleus assay) at doses of 100 microM and higher in oesophageal OE33 cells, but fails to induce such DNA damage below this cut-off dose. We also show that in terms of NF-kappaB activation (as measured by up-regulation of two NF-kappaB target genes) by DCA, a similar dose response is observed. This dose-response data may be important clinically as DCA exposure to the oesophagus may be used as a way to identify the 10% of Barrett's oesophagus patients currently progressing to cancer from the 90% of patients who do not progress. Only quantitative studies measuring DCA concentrations in refluxates correlated with histological progression will answer this question. We further show here that ROS are behind DCAs ability to activate NF-kappaB as antioxidants (epigallocatechin gallate, resveratrol and vitamin C) abrogate DCAs ability to up-regulate NF-kappaB-controlled genes. In conclusion, low doses of DCA appear to be less biologically significant in vitro. If this were to be confirmed in vivo, it might suggest that reflux patients with low DCA concentrations may be at a lower risk of cancer progression compared to patients with high levels of DCA in their refluxate. Either way, antioxidant supplementation may possibly help prevent the deleterious effects of DCA in the whole GI tract.