1. Molecular and Histopathologic Prognostic Factors in Rectal Cancer Monirath Hav, MD, Ph.D. fellow (VLIR project) Pathology Department Ghent University Hospital Promoters: Prof. Dr. Piet Pattyn & Prof. Dr. Claude Cuvelier

2. Prognostic value of MSI : a comparative study Cambodians : 37 cases Belgians : 39 cases Criteria : revised Bethesda guidelines IHC for MMR proteins  MSI testing? MSI status  prognosis

3. Literature review MSI occurs in 10-20% of colorectal cancer MSI in rectal cancer is a rare event (2%), but if present, is strongly associated with HNPCC M. Nilbert et al. Eur. J. of Cancer, issue 6, June 1999, Pages 942-945

4. What has been known about MSI in Belgian population ? MSI in colon CA : 12.4% MSI in rectal CA : 1.11% MSI has no prognostic value in colon cancer Vanessa Deschoolmeester et al. European Journal of Cancer 44 (2008) 2288-229

5. Hypothesis & questions Is there a difference in MSI status between the 2 populations? If yes, is there a difference in prognostic value of MSI? Based on your experience, how good is the correlation between IHC for MMR proteins & MSI testing?

6. MDM2 amplification negatively predicts response to neoadjuvant therapy in rectal cancer

7. Current study 71 cases  59 with neoadjuvant T. IHC: MDM2 & p53 on biopsies & resections p53 mutation analysis MDM2 Fluorescent In Situ Hybridization (FISH) : on biopsies Correlation with T downstaging and prognosis

9. The Two Major Apoptotic Pathways Ashkenazi A. Nat Rev Can 2002;2:420–430. Caspase 3, 6, 7 Apoptosis Pro-apoptotic ligand FADD FLIP DR5 DR4 Cell-extrinsic pathway Procaspase 8, 10 p53 Caspase 9 Caspase 8, 10 p53 BAX, BAK Mitochondria SMAC/DIABLO Chemotherapy Radiotherapy DNA damage PUMA, NOXA APAF1 Cytochrome c DNA damage IAP Cell-intrinsic pathway BCL2, BCLX L, MCL1 mdm2

10. Hypothesis Presence of MDM2 overexpression in rectal cancer ! MDM2 overexpression  -  wild-type p53 MDM2 overexpression  -  absence of p53 MDM2 overexpression / amplification no p53-dependent apoptosis no downstaging (no response to neoadjuvant)

11. MDM2 Amplification in endoscopic biopsy  Conventional chemoradiation T. does not work  Need for combination with targeted T. (i.e Nutlins & RITA inhibit mdm2-p53 binding )

12. Peri-tumoral inflammation : favorable prognostic factor in rectal cancer

13. Inflammation as favourable prognostic factor in 5 studies: –EORTC study. –Leuven study. –Cetuximab study. –Shia et al. Am J Surg Pathol 2004; 28: 215. –Knutsen et al. Oncol Rep 2006. No prognostic value: –Perez et al. J Gastrointest Surg 2007; 11: 1534. 5 positive studies: time from end neoadjuvant treatment to surgery always < 6 weeks, while at least 8 weeks in Perez et al.

14. Annelies Debucquoy et al. Eur. Journ. of Cancer 44 (2008) 791-797

15. The current study 71 patients (2005-2008 : stage I – III ; mean FU time = 18Ms ) 59 cases with neoadjuvant Interval neoadj-surgery : +/- 6 weeks Peri-tumoral inflammation (PTI): cut-off 25% T Downstaging (38 cases)  DFS & N+ PTI  tumor downstaging PTI  DFS Tumour deposits  DFS

16. Response to treatment causes tumor damage and necrosis, which increases inflammatory reaction and elicits a specific immune response: –Peritumoral inflammation correlates with T downstaging, which is a measure of tumor response to treatment. –Postoperative chemo tends to be effective when inflammation is present. –Prognostic value of inflammation increases with less time between end of neoadjuvant treatment and surgery (<6 weeks

17. Node status and DFS 0,2,4,6,8 1 Cum. Survival 0510152025303540 Time N + N -

18. Tumor deposits & DFS P=0.02 0,2,4,6,8 1 Cum. Survival 0510152025303540 Time TD + (<3mm) TD -

19. Downstaging & N + P=0.03 0 1 2 3 4 5 6 7 8 9 10 Nodes invaded 01

20. T downstaging & DFS P=0.02 0,2,4,6,8 1 Cum. Survival 0510152025303540 Time Downstaging No downstaging

21. Peri-tumoral inflammation & DFS 0,2,4,6,8 1 Cum. Survival 0510152025303540 Time PTI + PTI -

22. Now in need for more FU data from prof. Pattyn

23. References 1.Vanessa Deschoolmeester et al. MSI has no prognostic value in colon cancer in Belgian population. European Journal of Cancer 44 (2008) 2288-229 2.M. Nilbert et al. Microsatellite instability is rare in rectal carcinomas and signifies hereditary cancer. Eur. J. of Cancer, issue 6, June 1999, Pages 942-945 3.Terry Van Dyke. P53 and tumor suppression. N Engl J Med 356; 1 (2007) 4.Jean-Franc¸ois Millau et al. P53 transcriptional activities: A general overview and some thoughts. Mutation Research 681 (2009) 118–133 5.Nadia N Naski et al. The p53 mRNA-Mdm2 interaction. Cell Cycle 8:1, 31-34 (2009) 6.Christine M. Eischen and Guillermaina Lozano. P53 and MDM2: Antagonists or Partners in Crime? Cancer Cell 15, march 3, 2009 7.Annelies Debucquoy et al. Morphological features and molecular markers in rectal cancer from 95 patients included in the European Organization for Research and Treatment of Cancer 22921 trial: prognostic value and effects of preoperative radiochemo therapy. Eur. Journ. of Cancer 44 (2008) 791-797