We identified several mutations in driver genes among patients with ovarian endometrioid carcinomas that have not been previously reported, including the homologous recombination RAD51C gene, Notch signaling genes (NOTCH1–4), chromatin remodeling genes SMARCA1/4, transcription factor E2F1, receptor tyrosine kinase RET, and ABL1 kinase. The gene discussed is E2F1; the disease is ovarian endometrioid carcinoma.