The purpose of this study was to further investigate the role of
estrogen but especially
progesterone on epithelial ovarian
tumor development since previous studies have suggested a relationship between serum
progesterone,
progesterone receptor expression and prognosis. Serum
progesterone concentration, the immunohistochemical expression of
estrogen receptor alpha (ER),
progesterone receptor A/B (PR), Ki-67, Bcl-2, p53, apoptosis and morphology were determined in 33 patients, all with poorly differentiated surface epithelial ovarian
tumors of different types. ER was expressed in 79% and PR in 33% of the
tumors. This group of aggressive
tumors was highly proliferative as indicated by Ki-67 index (mean 38.9%), and in some cases proliferation appeared to be mainly located to areas with a high ER density. The majority of cases (76%), both receptor-positive and -negative, overexpressed p53. High ER expression was related to a lower apoptotic activity as compared with
tumors with a low expression of the ER (p = 0.008). Serum
progesterone in itself did not show any clear relationship to
steroid receptor status, expression of Ki-67, p53, Bcl-2 or signs of apoptosis. Survival in this small but homogeneous group of advanced
epithelial ovarian cancers, showed an improved survival rate in patients with high serum
progesterone, especially in combination with expression of
progesterone receptors (p = 0.04). In conclusion,
estrogen and
progesterone receptors in parallel with deranged p53 and Ki-67 were expressed to a great extent. The finding of a lower apoptotic activity in
tumors with a high expression of ER and an indication of increased proliferation in areas with high ER density gives a rationale for
antiestrogen therapy even in poorly differentiated
epithelial ovarian cancers. Improved survival is related to serum
progesterone, especially in combination with PR expression.