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Personalised Medicine in Colorectal Cancer? Mr Arfon G M T Powell MB ChB MSc MRCSEd Clinical Research Fellow in Surgery
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Colorectal cancer is the third most common cancer in the UK 39,991 new cases in 2008 Cancer Reseach UK. Bowel cancer statistics – UK, 2011. http://info.cancerresearchuk.org/cancerstats/types/bowel/
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CRC is the 2 nd most common cause of cancer-death Accounting for 16,259 deaths in 2009 Cancer Reseach UK. Cancer Mortality – UK Statistics 2011. http://info.cancerresearchuk.org/cancerstats/mortality/
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Treatment Treatment regimens are currently based on disease stage Surgery Chemotherapy – Curative – Palliative Biological therapy
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Prognosis Prognosis still remains stage dependent – Dukes’ A 93% – Dukes’ B 77% – Dukes’ C 48% Cancer Reseach UK. Bowel cancer statistics – UK, 2011. http://www.cancerresearchuk.org/cancer-help/type/bowel-cancer/treatment/statistics-and-outlook-for- bowel-cancer#outlook
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http://www.hopkinscoloncancercenter.org/CMS/CMS_Page.aspx?CurrentUDV=59&CMS_Page_ID=1F7C07D4-268D-4635-8975-70A594870CC8 Surgical approach to colorectal cancer
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Variation in biomarker prognostic value
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Colorectal cancer development Accumulation of genetic alterations – Vogelstein
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Microsatellite Instability Phenotype Distinct genomic instability pathway Microsatellite repeats Associated with loss of mismatch repair protein (MMR) function Improved outcome
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Söreide K, Janssen EA, Söiland H, Körner H, Baak JP. Microsatellite instability in colorectal cancer. Br J Surg 2006; 93:395-406.
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CpG Island Methylator Phenotype Hypermethylation of cytosine- and guanine-rich stretches of DNA, called CpG islands, in the promoter region of genes causes transcriptional silencing and has been implicated in carcinogenesis
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MSI/CIMP+ MSI/CIMP- Microsatellite stability status CIMP status CIMP +ve CIMP -ve MSI MSS MSS/CIMP+ MSS/CIMP- CIMP +ve CIMP -ve
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MSI/CIMP+ MSI/CIMP- Microsatellite stability status CIMP status CIMP +ve CIMP -ve MSI MSS MSS/CIMP+ MSS/CIMP- CIMP +ve CIMP -ve Good survival Poor survival
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MSI/CIMP+ MSI/CIMP- Microsatellite stability status CIMP status CIMP +ve CIMP -ve MSI MSS MSS/CIMP+ MSS/CIMP- CIMP +ve CIMP -ve Prognostic information remains unclear
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Serrated Adenocarcinoma Proximal location MSI positive Outcome variable which depends on tumour site http://kathrin.unibas.ch/polyp/bilder/gross/p015-03.jpg Serrated Adenocarcinoma Non Serrated Adenocarcinoma
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Our experience with performing MSI and CIMP status analysis on colorectal tumours
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Study design Retrospective study of 750 FFPE tumours IHC for MMR proteins (MLH1, MSH2, MSH6 and PMS2) 40% tumour required within the section for PCR MSI PCR analysis of: – BAT 25 – BAT 26 – MONO 27 – NR-21 – NR-24
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Technical issues 55% of patients required macroscopic dissection to the equivalent of 2 10micron sections
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Technical issues 55% of patients required macroscopic dissection to the equivalent of 2 10micron sections
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MSI +ve MSI -ve
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Preliminary results on 233 patients Not significantly associated with: – Increasing age (P=0.168) – Dukes stage (P=0.054) – Poor differentiation (P=0.362) – Vascular invasion (P=0.176) – Anaemia (P=0.192) – Raised CRP (P=0.374) – Hypoalbuminaemia (P=0.541) – Emergency presentation (P=0.943) Significantly associated with: – Right colon location (P<0.001) – Polypoid morphology (P=0.031) – Lower lymph node ratio (P=0.040) – Mucin production (P=0.009) – Serrated adenocarcinoma (P<0.001)
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P=0.042 The relationship between MSI status and cancer-specific survival
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CIMP study design Extracted DNA requires bisulfite conversion Followed by a methylight PCR assay for – CACNA1G – IGF2 – NEUROG1 – RUNX3 – SOCS1
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DNA recovery following bisulfite treatment DNA recovery following bisulfite treatment is variable and does not reach the projected > 75% PatientInput (ng)nano drop (ng/ul)DNA recovered (ng)Percentage recovered (%) 13503.97822.3 23504.38624.6 33502.85616.0 435028560160.0 53502.55014.3 63503.46819.4 73503.77421.1 83503.46819.4 92000.363.0 10300841680560.0 113501.7349.7 12200641280640.0 133503.77421.1 143002.85618.7 153001.53010.0 163004.89632.0
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MSI and CIMP status as predictors of response to treatment
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Treatment A Curative resection surgery B CResection surgery + adjuvant therapy (eg. Chemothearpy) DDependent on tumour characteristics
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Treatment of colorectal cancer Surgery remains the primary modality for cure Chemotherapy for high risk patients – Lymph node involvement – Locally advanced tumours MDT decision Difficulty identifying patients that benefit from chemotherapy
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Adjuvant Chemotherapy 2 major regimens for CRC treatment: – FOLFIRI (5-FU, folinic acid [Leucovorin], and irinotecan [Campostar]) – FOLFOX (5-FU, folinic acid [Leucovorin], and oxaliplatin [Eloxatin])
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Adjuvant Chemotherapy 2 major regimens for CRC treatment: – FOLFIRI (5-FU, folinic acid [Leucovorin], and irinotecan [Campostar]) – FOLFOX (5-FU, folinic acid [Leucovorin], and oxaliplatin [Eloxatin]) Results in context of MSI is conflicting
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Conclusions Colorectal cancer tumour heterogeneity exists Techniques validated MSI+/CIMP+ confers improved survival Response to treatment remains unclear
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Acknowledgments I would like to thank Dr David Baty and Christine Black (Molecular Genetics, Dundee) for their expertise with the MSI analysis I would like to thank Rachael Ellis (Molecular Genetics, Glasgow) for her help with the bisulfite treatments I would like to thank Clare Orange for her continued help over the last 3 years!
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Thank you!
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