Combining conventional and stroma-derived tumour markers in pancreatic ductal adenocarcinoma

BACKGROUND: A lack of disease-specific symptoms and good tumour markers makes early detection and diagnosis of pancreatic ductal adenocarcinoma (PDAC) challenging. OBJECTIVE: To analyse the tissue expression and circulating levels of four stroma-derived substances (type IV collagen, endostatin/type XVIII collagen, osteopontin and tenascin C) and four conventional tumour markers (CA 19-9, TPS, CEA and Ca 125) in a PDAC cohort. METHODS: Tissue expression of markers in normal pancreas and PDAC tissue was analysed with immunofluorescence. Plasma concentrations of markers were measured before and after surgery. Patients with non-malignant disorders served as controls. RESULTS: The conventional and stromal substances were expressed in the cancer cell compartment and the stroma, respectively. Although most patients had increased levels of many markers before surgery, 2/12 (17%) of patients had normal levels of Ca 19-9 at this stage. High preoperative endostatin/type XVIII collagen, and postoperative type IV collagen was associated with short survival. Neither the pre-nor postoperative levels of TPS, Ca 125 or CA 19-9 were associated to survival. CONCLUSIONS: PDAC is characterized by an abundant stroma. These initial observations indicate that the stroma can be a source of PDAC tumour markers that are found in different compartments of the cancer, thus reflecting different aspects of tumour biology.