Protocol for quantifying drug sensitivity in 3D patient-derived ovarian cancer models

Three-dimensional (3D) ex vivo cultures allow the study of cancer progression and drug resistance mechanisms. Here, we present a protocol for measuring on-target drug sensitivity in a scaffold-free 3D culture system through quantification of apoptotic tumor cells. We provide detailed steps for sample processing, immunofluorescence staining, semi-high-throughput confocal imaging, and imaged-based quantification of 3D cultures. This protocol is versatile and can be applied in principle to any patient-derived material.