Elevated ULK1 expression is a negative predictor of patient survival and patient-derived HGSOC spheroids are susceptible to ULK1 inhibition. A. Correlation of low and high ULK1 expression with overall survival (n=1023) and progression-free survival (n=957) among stage III-IV serous ovarian cancer patients using TCGA and GEO gene expression microarray datasets from the online tool accessed at www.kmplot.com/ovar. Hazard ratios and log rank tests indicate a significantly worse prognosis due to high ULK1 expression in advanced-stage serous ovarian tumors. B. Three new patient-derived HGSOC cell lines (iOvCa147, iOvCa256, and iOvCa360) were cultured as spheroids with or without 5 µM MRT68921. Phase contrast images were captured at 72 h after seeding; scale bars represent 250 µm. Number of live cells in untreated and MRT68921-treated spheroids were counted using Trypan Blue Exclusion. Data is displayed as mean ± SEM (n=4) percentage of live cells in MRT68921-treated spheroids normalized to untreated spheroids set to 100%. Student’s t-test, **P,0.01, ****P<0.0001.