Starting from these results, the aim of the present study was to search for and investigate functional relationships between ERα and DOT1L in PEO1 and PEO4 HGSOC cells, which are models representing the tumor at its first recurrence and after a second relapse due to the acquisition of chemo-resistance, respectively, and expressing both ERα and DOT1L at appreciable levels. The gene discussed is ESR1; the disease is neoplasm.