Abstract B43: Early detection biomarker of pancreatic cancer using a nanoparticle-based methylation assay

Pancreatic cancer is a deadly cancer with an overall 5-year survival rate of less than 5% and no improvements in survival over the last 3 decades. Pancreatic cancer currently ranks as the fourth leading cause of cancer related death in United States with an estimated 42,470 new cases and 35,240 deaths in 2009 and its incidence is rising. One of the major factors attributed to the dismal prognosis of pancreas cancer is their delayed diagnosis such that only about 10% cases are amenable to potential curative surgical resection. However, long term 5-year survival is attainable in selected patients with early-stage pancreatic cancer who can undergo curative surgical resection. Early detection of pancreatic cancer is, therefore, thought to be the best modality for improving survival in this lethal disease. However, no screening test currently exists for pancreatic cancer. In recent years, it has become apparent that pancreatic cancer is as much a disease of mis-regulated epigenetics as it is a disease of genetic mutation. In particular, changes in DNA promoter methylation patterns could play a crucial role in tumorigenesis and cancer progression. In order to address the need for both clinical diagnostics as well as therapeutics, many studies have employed DNA methylation of specific genes for application in diagnostics of multiple cancers. Detection of cancer specific, abnormally DNA methylated gene promoter sequences has emerged as one of the leading tumor, biomarker detection strategies. We have used a genome-wide transcriptome approach to identify new cancer specific DNA methylation alteration in pancreatic carcinoma. We analyzed methylation frequencies of best candidate genes, BNC1 and ADAMTS1, by MSP and qMSP as well as expression analysis by real-time PCR and immunohistochemistry. We use a novel nanoparticle-enabled MOB (Methylation On Beads) technology to detect very early stages of the pancreatic cancers. The biological role of BNC1 gene was examined by colony formation, cell proliferation, and invasion assays in pancreatic cancer cell lines. We identified 2 novel genes BNC1 (91.8%) and ADAMTS1 (66.7%) that showed a high frequency of methylation in pancreas cancer tissues (n=143). BNC1 was frequently methylated in the earliest stages of pancreas carcinogenesis including carcinoma in situ or pancreatic intraepithelial neoplasia PanIN3 (100%) and Stage 1 invasive cancers (97.4%). Using the ultrasensitive nanoparticle-enabled MOB assay, these alterations could be detected in serum samples from patients with pancreas cancer, with a sensitivity for BNC1 of 79% (95% CI: 0.6–0.8) and for ADAMTS1 of 48% (95% CI: 0.3–0.6) (n=42 cancers, Stages 1–4), while specificity was 88% for BNC1 (95% CI: 0.6–0.9) and 92% for ADAMTS1 (95% CI: 0.7–0.9) among 26 individuals without cancer. BNC1 overexpresstion in pancreatic cancer cell lines showed suppressive effect by colony formation, cell proliferation but not invasion. Both BNC1 and ADAMTS1 had high sensitivity for the earliest stages of pancreas cancers. Notably, BNC1 and ADAMTS1 show the potential power of using circulating DNA for early detection of cancer, especially in high risk individuals. Moreover, BNC1 is a candidate tumor suppressor gene in pancreatic cancer which is inactivated by promoter DNA methylation. Citation Information: Cancer Epidemiol Biomarkers Prev 2011;20(10 Suppl):B43.