Abstract

Nanodiagnostic Tool for Comprehensive Assessment of Cancer in Blood

Shan Wang, Leland T. Edwards Professor in the School of Engineering, Stanford University

Blood borne biomarkers, such as secreted proteins, circulating tumor DNA (ctDNA) and circulating tumor cell (CTC), have garnered much attention as minimally invasive cancer biomarkers for the “liquid biopsy” of tumors over the past decade. In this talk, we will describe three magnetic-nanoparticle-based diagnostic tools that have been used to assess cancer in peripheral blood successfully: 1) Stanford spin-off MagArray Inc. has launched REVEAL, a cancer-specific blood test that may aid clinicians in characterizing indeterminate pulmonary nodules (4-30mm) in current smokers aged 25-85. The REVEAL Score is calculated using an algorithm based on the measurement of 3 clinical factors and 3 blood proteins associated with the presence of lung cancer. The assay is optimized to rule out lung cancer with a negative predictive value (NPV) of = 95%.  2) We have developed sequence-specific capture of hypermethylated or mutated genes of interest from cfDNA for early detection of NSCLC and colorectal cancer (CRC). With downstream analysis of PCR products on giant magnetoresistive (GMR) biosensors and high-resolution melt analysis for a highly multiplexable assay, we have achieved a sensitivity of 0.01% mutant/methylated allele fractions. Our optimized assay has the ability to detect down to 16 pg (~4 genome equivalents) of hypermethylated DNA spiked-in to 3.5 mL of plasma. 3) We have utilized the MagSifter and immunocytochemistry combined with automated image analysis and machine learning techniques (random forest, transfer learning) for the enumeration and diagnosis/prognosis of NSCLC derived CTCs in patient samples, which are well suited for therapy selection and monitoring.