This is a phase 2 study of investigational drug niraparib in patients with advanced/recurrent
endometrial cancer. The purpose of this study is to determine whether blocking a protein
called poly (ADP-ribose) polymerase (PARP) with niraparib provides clinical benefit in
patients with recurrent endometrial cancer, as well as to explore the possible impact of
phosphatase and tensin homolog (PTEN) loss (loss of function of the PTEN gene) on blocking
PARP with niraparib.