VOL. 7, No. 1/2, December 2011

Y. Niv [2011] Med. Hypotheses Res. 7: 35-37.

Estrogen Receptor β May Be a Tumor Suppressor Gene
in Colorectal Cancer of Inflammatory Bowel Disease

Yaron Niv*

Department of Gastroenterology, Rabin Medical Center, Tel Aviv University, Israel

Abstract. Gender effect on the incidence and prognosis of colorectal cancer (CRC),
sporadic and on the back ground of inflammatory bowel disease, is unique by protecting
women till the age of menopause. This protection disappears in older women and cancer risk
becomes similar to men. There are two types of estrogen receptors, ERα and ERβ. ERα is a
nuclear receptor for 17β-estradiol, and presented in the female reproductive system. ERβ is
found in the colon. It was demonstrated that silencing of ERβ by mutation or by promoter
methylation increased proliferation and carcinogenesis. Furthermore, Malignant colon tissue
showed a selective loss of ERβ protein expression when compared to normal colon mucosa in
the same patient, and loss of ERβ expression in CRC is associated with more advanced
staging. Long standing ulcerative colitis or Crohn's colitis patients are in danger of
developing CRC. The potential role of ERβ as a tumor suppressor gene in CRC of colitis
patients has never been investigated. Proving this hypothesis and finding a way to induce
ERβ expression in these patients by an agent that will not attached to ERα and induces
estrogen feminine side effects in men, will be a potential therapy preventing development of

* Correspondence: Dr. Yaron Niv, Department of Gastroenterology, Rabin Medical Center,
39 Jabotinski Street, Petach Tikva 49100, Israel. TEL : 972-3-9377237. FAX: 972-3-9210313.