Abstract 191: Desmoplasia in primary tumors and metastatic lesions of pancreatic cancer

Abstract Pancreatic ductal adenocarcinoma (PDAC) is a major cause of cancer-related death in the United States. PDAC is characterized by high levels of fibrosis, a feature termed desmoplasia. Desmoplasia is thought to hamper the efficacy of therapeutics treating PDAC. Agents targeting components of the tumor stroma have shown some enhancement of first-line therapeutics targeting tumor cells. As metastatic burden is one of the primary causes for mortality in PDAC, the question remains of whether stromal targeting therapeutics will benefit patients with late stage, metastatic disease. We sought to address this question by assessing the extent of desmoplasia in both primary PDAC tumors and metastatic lesions of pancreatic origin. Patient tissue staining using a pentachrome or standard immunohistochemical technique demonstrates that extracellular matrix components, such as collagen, are found in high levels in both primary tumors and metastatic lesions. The difference in the level of desmoplasia in primary tumors and metastatic lesions was statistically insignificant. We also observed a significant correlation between patient survival and extracellular matrix deposition. Kaplan-meier curves for collagen I showed median survival of 527 days in low collagen patients, and 176.5 in high level patients. Low level hyaluronan patients displayed median survival times of 2107 days as compared to 385 days in high level patients. Our results indicate that both primary tumors and metastases of PDAC have highly fibrotic stroma. Thus, stromal targeting agents may benefit PDAC patients, even those with metastatic disease. Citation Format: Clifford J. Whatcott, Aprill Watanabe, Janine LoBello, Daniel Von Hoff, Haiyong Han. Desmoplasia in primary tumors and metastatic lesions of pancreatic cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 191. doi:10.1158/1538-7445.AM2014-191