All of the following may predispose to Endometrial Ca, except:
Oral contraceptives will not predispose to Endometrial Ca. Ref: Current Obs and Gynae Diagnosis and Treatment, 9th Edition, Page 916 ; Shaw's Textbook of Gynaecology, 12th Edition, Pages 302-3
Un-opposed Estrogen
Oral contraceptive
Radiation
Tamoxifen therapy