Pancreatic cancer (PC) is the fourth leading cause of cancer death in Western societies. Despite significant progress in understanding the molecular pathology of PC and its precursor lesion: pancreatic intraepithelial neoplasia (PanIN), there remain no molecules with proven clinical utility. Affymetrix Genechipfi oligonucleotide microarrays were used to interrogate mRNA expression of PC and normal pancreas to identify molecular pathways dysregulated in PC. Analysis of these data identified altered expression of numerous components of the S100 Calcium Binding Protein Family, Retinoic Acid signalling pathway and the HOX transcriptional network in PC compared to normal pancreas. These pathways were assessed using immunohistochemistry (IHC) and in-situ hybridisation (ISH) in a cohort of patients with PC. Increased protein expression, of S100A2, S100A6 and S100P was observed in 43%, 60% and 48% of PC respectively. Expression of S100A2 was associated with a poor outcome (p = 0.009), whilst increased expression of S100A6 (p = 0.0008) and S100P (p = 0.0005) were associated with an improved outcome. Additionally, S100A2 expression was identified as an independent marker of outcome in resected tumours. Aberrant expression of retinoic acid signalling components was demonstrated in PC cell lines using semi-quantitative RT-PCR. ISH demonstrated expression of Retinoic Acid Induced 3 (RAI3), an orphan G protein coupled receptor normally expressed in the fetal lung, in 68% of PC, and this co-segregated with an improved overall survival (p = 0.026).Ectopic protein expression of HOXB2, a transcription factor normally expressed in the developing hindbrain and modulated by retinoic acid, was observed in 15% of early PanIN lesions and 38% of PC specimens. Expression of HOXB2 was associated with non-resectable tumours and was an independent predictor of poor survival in resected tumours. Suppression of HOXB2 protein expression using small interfering RNA, resulted in epithelioid trans-differentiation in the Panc-1 PC cell line, however no alteration in proliferation rates were observed compared to controls. This thesis has shown that transcript profiling and tissue validation has identified potential markers of early diagnosis and outcome in PC. Furthermore, pathways and molecules previously thought to be associated with normal human development have been implicated to play a role in the development and progression of PC. Further analyses of these markers will determine any potential role in future diagnostic and therapeutic strategies.

The aim of the present study was to assess whether the changes in the epithelial glycoproteins seen in the mucosa adjacent to tumors are specific premalignant markers or secondary reactive phenomena. A secondary objective was to assess whether ulcerative colitis and Crohn's Disease could be distinguished from one another histochemically. The carbohydrate prosthetic groups from colonic epithelial glycoproteins were characterized histologically and histochemically from 17 cases of ulcerative colitis, 21 cases of Crohn's Disease and 19 cases of diverticular disease. Two histochemical parameters - the relative proportion of sulpho- and sialomucin and the side-chain substitution pattern of O-acetylated sialic acid - were assessed using a battery of seven histochemical techniques. Serial sections from each specimen were also evaluated morphologically, using hematoxylin and eosin. In addition, the patterns of O-acetylated side-chain sialic acid from the three inflammatory bowel diseases were compared to data previously acquired from the mucosa adjacent to colonic tumors. Results indicate that neither focal changes nor the predominance of sialomucins are specific to the mucosa adjacent to tumors. As well, changes in one histochemical parameter were independent of changes in the other parameter. No histochemical class of epithelial glycoproteins was specific to any of the inflammatory bowel diseases and, therefore, it was not possible to distinguish between ulcerative colitis and Crohn's Disease on the basis of the histochemical techniques used in the present study. It was also noted that the histochemical changes in ulcerative colitis, Crohn's Disease and diverticular specimens were not related to the degree of inflammation. Finally, as a group, Crohn's Disease specimens showed a loss of sulphomucin-sialomucin gradient along the length of the crypts. / Medicine, Faculty of / Pathology and Laboratory Medicine, Department of / Graduate