The following Specific Aims are proposed: Specific Aim 1: Apply partial wave spectroscopy (PWS) to improve the ability of cytology to diagnose PC. They will assess fixed cytological samples previously obtained either by ERCP or EUS that were positive and negative to develop prediction rules and, importantly, test it in samples including a subgroup who were cytologically negative but later were diagnosed with pancreatic cancer. The completion of this study will also show the feasibility of a multi-institutional clinical trial where cytology specimens can be reliably exchanged for PWS analysis. Specific Aim 2: Demonstrate the potential of PWS to correctly identify patients with concurrent pancreatic cancer based on the analysis of fresh cytological specimens. From the perspective of future clinical applications, PWS can be potentially used on either fixed or fresh cytological samples. Thus, it is important to compare the diagnostic performance of PWS between these two types of cytological preparations (i.e., fixed vs. fresh cells) and determine which one provides the optimal diagnostic performance.
