A novel gene expression signature in peripheral blood mononuclear cells for early detection of colorectal cancer

Transcription

1 A novel gene expression signature in peripheral blood mononuclear cells for early detection of colorectal cancer C. Nichita, L. Ciarloni, S. Monnier-Benoit, S. Hosseinian, G. Dorta & C. Rüegg Aliment Pharmacol Ther 2014; 39:

2 Introduction CRC screening 3rd most common cancer, 2nd leading cause of cancer related death in Europe Indication for mass screening, beginning at age 50 Colonoscopy goldstandard - Invasiveness, low compliance non-invasive methods: ifobt, gfobt - Compliance with feacal test suboptimal Need non- or minimal invasive, compliant, cost-effective and accurate test to detect adenomatous polyps and early CRC

3 Blood based screening Several approaches Blood-borne tumour markers/tumor derived molecules Presence of circulating tumour cells Host-response to tumour-derived signals Local (host)factors in tumour microenvironment necessary for tumour progression Peripheral blood mononuclear cells (PBMC) gene expression profiles associated with breasts, renal, pulmonary, bladder and digestive cancers Aim of study: identify gene expression signatures in PBMC to discriminate patients with AP and CRC from healthy controls and to define predicitve classifiers

4 Methods Monocentric case-control study, Lausanne CHUV 03/ /2009 Exclusion criteria: age<18; alcohol/drug abuse; severe cardiorespiratory-, renal-, liver- or GI-disease; HNPCC, FAP All patient obtained colonoscopy Blood withdrawn before polypectomy or biopsie Groups: Control (n=41) without colon lesion Adenoma (n=21) CRC (n=23) IBD (n=22) non CRC-cancer (n=14) (no colonoscopy)

5 Gene processing PBMC separation and RNA extraction Digital gene expression & tag-profiling (Illumina Genome analyzer II GeneSifter Analysis software) Reverse transcription & Single-channel quantitative multiplex PCR Statistical analysis (univariate & multivariate methods) Subset CRC/control Subset AP/control Validation by non-overlapped bootstrap method

6 Results

7 Biomarker identification

8 Biomarker identification Total of gene transcripts 8843 genes underwent differential gene expression analysis (p<0.05 and fold change >2) 54 gene data included

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10 Biomarker identification

11 CRC classifier Sensitivity 78%, specificity 92% Adenoma classifier sensitivity 46%, specificity 92%

12 Results Most genes involved in inflammatory process IBD: specificity CRC & AP classifier 91% resp. 96% Sensitivity for other cancers: no classifier responded -> classifier specific for colorectal tumours

13 Discussion Study was able to identify classifiers for AP and CRC and discriminate them Identified genes specific for colorectal tumours Detection rate for adenoma (46%) superior to FIT (20-29%) or Septin 9 test (11%) no comparison with existing screening methods

14 Conclusion Prove of concept to screen patient with average risk Attractive and simple methode for cancer detection Limitations: Small sample size Model performance overestimated Sample size to small to stratify sensitivity by cancer stage Gene signature not validated in an independent set of control, cancer and adenoma Study not designed to be age-matched, included patients <50y Large multi-centric study to follow

15 press release Colox to be released in Switzerland by end 2014