Ovarian cancer begins in the ovaries. Women have 2 ovaries, one on each side of the uterus in the pelvis, as shown in the picture below. The ovaries produce eggs (called ova). They are also the main source of a woman's female hormones, estrogen and progesterone. The eggs travel through the fallopian tubes to the uterus. Here they may be fertilized and develop into a fetus.
The ovaries contain 3 kinds of tissue:
epithelial cells, which cover the ovary
germ cells, which make eggs (ova) inside of the ovary
stromal cells, which make most of the female hormones (estrogen and progesterone)