Nuclear condensates in human tissue and in vitro. (A) Model illustrating potential behaviors of small molecules in nuclear condensates. (B–C) Immunofluorescence of scaffold proteins of various nuclear condensates in tissue biopsies from benign and malignant human breast (B), and benign and malignant colon tissue (C), in nuclei stained with Hoechst, imaged at 100× on a fluorescent confocal microscope (see also Figures S1, S2). (D) Schematic of in vitro droplet formation assay to measure small molecule partitioning into nuclear condensates. (E) In vitro droplet assay showing the behavior of fluorescein dye in the presence of six protein condensates formed in 125mM NaCl and 10% PEG, with 10μM protein and 5μM fluorescein, imaged at 150× on a confocal fluorescent microscope (see also Figures S3–S6). Quantification of enrichment of the drug is shown to the right, error bars represent SEM.