Ovarian cancer is a cancerous tumor of an ovary.[10] It may originate from the ovary itself or more commonly from communicating nearby structures such as fallopian tubes or the inner lining of the abdomen.[3][11] The ovary is made up of three different cell types including epithelial cells, germ cells, and stromal cells.[12] When these cells become abnormal, they have the ability to divide and form tumors. These cells can also invade or spread to other parts of the body.[13] When this process begins, there may be no or only vague symptoms.[1] Symptoms become more noticeable as the cancer progresses.[1][14] These symptoms may include bloating, vaginal bleeding, pelvic pain, abdominal swelling, constipation, and loss of appetite, among others.[1] Common areas to which the cancer may spread include the lining of the abdomen, lymph nodes, lungs, and liver.[15]

Reference
Wiki: Ovarian epithelial carcinoma