Evaluation and modification of tumor cell isolation techniques from malignant effusions for rapid drug sensitivity testing

Non-small cell lung cancer treatment decisions rely on several diagnostic steps. Tests that rely on DNA sequencing often fail to capture the full mutational landscape of tumor cells, and drug sensitivity testing (DST) has limitations hindering widespread use currently. One of the major challenges for DST is the rapid isolation of a sufficient number of live tumor cells that would allow testing of multiple drugs simultaneously. To address this challenge, we have developed a DST procedure specifically tailored for tumor cells originating from malignant pleural effusions. We first identified tumor cells by anti-epithelial cell adhesion molecule (EpCAM) flow cytometry and then compared several methods for tumor cell isolation: immunomagnetic enrichment of epithelial cells using EpCAM, negative selection via immunomagnetic CD45⁺ cell depletion, and size-based separation and capture of tumor cells utilizing cell strainers. Of these methods, repeated rounds of CD45⁺ cell depletion, in which the number of rounds is set by the initial percentage of tumor cells in the sample, were the most effective. By combining tumor cell enrichment with DST, we have developed a system which generates DST results that correlate with clinical outcomes.