Ascites analysis by a microfluidic chip allows tumor-cell profiling

Significance Serial molecular analyses of tumor cells during treatment- and biopsy-driven clinical trials are emerging norms for many cancers. Yet surgical and image-guided biopsies are expensive and invasive, explaining why alternative sources for tumor cells are being sought. In ovarian cancer (and other abdominopelvic cancers), abdominal fluid buildup (ascites) occurs frequently. We demonstrate that ascites tumor cells (ATCs) present a valuable source of tumor cells, rendering ascites another form of “liquid biopsy.” We evaluated 85 ovarian cancer-related markers and developed a unique, low cost miniaturized microfluidic ATC chip for on-chip enrichment and molecular profiling using small amounts of ascites. This approach could expand the utility of ATCs within cytotoxic and/or molecularly targeted ovarian cancer therapeutic trials. Ascites tumor cells (ATCs) represent a potentially valuable source of cells for monitoring treatment of ovarian cancer as it would obviate the need for more invasive surgical biopsies. The ability to perform longitudinal testing of ascites in a point-of-care setting could significantly impact clinical trials, drug development, and clinical care. Here, we developed a microfluidic chip platform to enrich ATCs from highly heterogeneous peritoneal fluid and then perform molecular analyses on these cells. We evaluated 85 putative ovarian cancer protein markers and found that nearly two-thirds were either nonspecific for malignant disease or had low abundance. Using four of the most promising markers, we prospectively studied 47 patients (33 ovarian cancer and 14 control). We show that a marker set (ATCdx) can sensitively and specifically map ATC numbers and, through its reliable enrichment, facilitate additional treatment-response measurements related to proliferation, protein translation, or pathway inhibition.