The virtual lack of well-characterized metastatic pancreatic cancer tissues for study has limited systematic studies of the metastatic process of this deadly disease. To address this important issue, we have instituted a rapid autopsy protocol for the collection of high quality tissues from patients with metastatic pancreatic cancer, called the Gastrointestinal Cancer Rapid Medical Donation Program (GICRMDP). At the time of preparation of this manuscript, 20 patients with metastatic pancreatic cancer and one patient with metastatic colon cancer have undergone a rapid autopsy in association with the GICRMDP. The average time interval achieved for these 21 patients was 8.0 hours, with more than 500 individual samples of matched high quality primary and metastatic pancreatic cancer tissues, peritoneal/pleural fluid and blood obtained so far. For the first four patients in which the autopsy was performed in <6 hours, we have successfully xenografted the primary tumor and/or two to four independent matched metastases from a variety of target organ sites, with a take rate of almost 60% for the first 26 xenografted tumors attempted. In an initial survey of KRAS2, TP53 and DPC4 genetic status in lethal metastatic pancreatic cancers, activating KRAS2 mutations were detected in 82% of cases and inactivating TP53 mutations in 55% of cases, consistent with rates of genetic alteration of these genes in early stage pancreatic cancers. However, DPC4 inactivation was found in 75% of patients analyzed, suggesting that genetic inactivation of the DPC4 tumor suppressor gene continues to be selected for with growth at the primary site and metastatic spread to other organs. The invaluable tissue resources generated by the success of the GICRMDP will provide an unparalleled resource for study of metastatic pancreatic cancer and of the metastatic process in general.

EphA2 is a transmembrane receptor tyrosine kinase that functions in the regulation of cell growth, survival, angiogenesis, and migration and EphA2 targeting has been proposed as a novel therapeutic strategy for neoplasms that overexpress this protein. EphA2 overexpression has been correlated with increased invasive and metastatic ability in pancreatic cancer cell lines. However, the patterns of EphA2 expression in human pancreatic cancers and associated metastases is unknown, as are the genetics of EphA2 in this tumor type. We collected clinicopathologic data and paraffin-embedded materials from 98 patients with primary and/or metastatic pancreatic cancer and performed immunohistochemical labeling for EphA2 protein. EphA2 protein immunolabeling was found in 207 of 219 samples (95%). The expression was predominantly cytoplasmic, although predominant membranous staining was observed in a minority of cases. When evaluated specifically for labeling intensity, primary and metastatic carcinomas were more strongly positive compared to benign ducts and PanIN lesions (P < 0.00001 and P < 0.01, respectively) and poorly differentiated carcinomas were more strongly positive for EphA2 than well and moderately differentiated tumors (P < 0.005). When primary carcinomas without metastatic disease were specifically compared to carcinomas with associated metastatic disease, the advanced carcinomas showed relatively less strong positive labeling for EphA2 (P < 0.008). Moreover, decreased EphA2 labeling was more commonly found in liver (P < 0.002), lung (P < 0.004) or peritoneal metastases (P < 0.01) as compared to distant lymph node metastases (P < 0.01). Genetic sequencing of the tyrosine kinase domain of EPHA2 in 22 samples of xenograft enriched pancreatic cancer did not reveal any inactivating mutations. However, EPHA2 amplification was found in 1 of 33 pancreatic cancers corresponding to a lymph node metastasis, indicating EPHA2 genomic amplification may underlie EphA2 overexpression in a minority of patients. Our data confirms that EphA2 is overexpressed in pancreatic cancer, but suggests a relative loss of EphA2 in co-existent pancreatic cancer metastases as well as a role for EPHA2 in organ specific metastasis.

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