‘Spheroid-sized’ MDTs (380 μM diameter and 300 μM height) were maintained in a microfluidic device with regular medium replacement for up to 8 days. Viability was determined on chip by confocal microscopy and off-chip by flow cytometry on dissociated cells (annexin V and 7AAD, xenograft only). A proof of concept experiment showed carboplatin chemosensitivity testing on a primary ovarian cancer tissue. The gene discussed is ANXA5; the disease is ovarian cancer.