Functional estrogen receptor signal transduction pathway activity and antihormonal therapy response in low-grade ovarian carcinoma.

BACKGROUND: Advanced low-grade ovarian carcinoma (LGOC) is difficult to treat. In several studies, high estrogen receptor (ER) protein expression was observed in patients with LGOC, which suggests that antihormonal therapy (AHT) is a treatment option. However, only a subgroup of patients respond to AHT, and this response cannot be adequately predicted by currently used immunohistochemistry (IHC). A possible explanation is that IHC only takes the ligand, but not the activity, of the whole signal transduction pathway (STP) into account. Therefore, in this study, the authors assessed whether functional STP activity can be an alternative tool to predict response to AHT in LGOC. METHODS: Tumor tissue samples were obtained from patients with primary or recurrent LGOC who subsequently received AHT. Histoscores of ER and progesterone receptor (PR) were determined. In addition, STP activity of the ER STP and of six other STPs known to play a role in ovarian cancer was assessed and compared with the STP activity of healthy postmenopausal fallopian tube epithelium. RESULTS: Patients who had normal ER STP activity had a progression-free survival (PFS) of 16.1 months. This was significantly shorter in patients who had low and very high ER STP activity, with a median PFS of 6.0 and 2.1 months, respectively (p < .001). Unlike ER histoscores, PR histoscores were strongly correlated to the ER STP activity and thus to PFS. CONCLUSIONS: Aberrant low and very high functional ER STP activity and low PR histoscores in patients with LGOC indicate decreased response to AHT. ER IHC is not representative of functional ER STP activity and is not related to PFS.

Cyclic activity of signal transduction pathways in fimbrial epithelium of the human fallopian tube.

INTRODUCTION: The local environment of the fallopian tube represents the optimal conditions for reproductive processes. To maintain tissue homeostasis, signal transduction pathways are thought to play a pivotal role. Enhancing our understanding of functional signal transduction pathway activity is important to be able to clarify the role of aberrant signal transduction pathway activity leading to female subfertility and other tubal diseases. Therefore, in this study we investigate the influence of the hormonal cycle on the activity of key signal transduction pathways in the fimbrial epithelium of morphologically normal fallopian tubes. MATERIAL AND METHODS: We included healthy pre- (n = 17) and postmenopausal (n = 8) patients who had surgical interventions for benign gynecologic conditions. Histologic sections of the fallopian tubes were reviewed by two pathologists and, for the premenopausal patients, hormone serum levels and sections of the endometrium were examined to determine the hormonal phase (early follicular [n = 4], late follicular [n = 3], early luteal [n = 5], late luteal [n = 5]). After laser capture microdissection, total mRNA was extracted from the fimbrial epithelium and real-time quantitative reverse transcription-PCR was performed to determine functional signal transduction pathway activity of the androgen receptor (AR), estrogen receptor (ER), phosphoinositide-3-kinase (PI3K), Hedgehog (HH), transforming growth factor-beta (TGF-ß) and canonical wingless-type MMTV integration site (Wnt) pathways. RESULTS: The early luteal phase demonstrated high AR and ER pathway activity in comparison with the late luteal phase (p = 0.016 and p = 0.032, respectively) and low PI3K activity compared with the late follicular phase (p = 0.036), whereas the late luteal phase showed low activity of HH and Wnt compared with the early follicular phase (both p = 0.016). Signal transduction pathway activity in fimbrial epithelium from postmenopausal patients was most similar to the early follicular and/or late luteal phase with regard to the AR, ER and PI3K pathways. Wnt pathway activity in postmenopausal patients was comparable to the late follicular and early luteal phase. We observed no differences in HH and TGF-ß pathway activity between pre- and postmenopausal samples. The cyclic changes in signal transduction pathway activity suggest a stage-specific function which may affect the morphology and physiology of the human fallopian tube. CONCLUSIONS: We demonstrated cyclic changes in activity of the AR, ER, PI3K, HH and Wnt pathways throughout the hormonal cycle.

Functional estrogen receptor signaling pathway activity in high-grade serous ovarian carcinoma as compared to estrogen receptor protein expression by immunohistochemistry.

PURPOSE: Anti-estrogen therapy may be used as a palliative treatment option in high-grade serous ovarian carcinomas (HGSC). However, clinical implementation is limited as the use of estrogen receptor (ER) protein expression by immunohistochemistry remains insufficient in predicting therapy response. To determine the accuracy of ER protein expression as a marker for ER signaling pathway activity, we aimed to correlate ER protein expression to functional ER signaling pathway activity in HGSC. METHODS: Immunohistochemical ER protein expression was visually scored using total percentages of stained tumor cells and histoscores. Subsequently, mRNA was extracted, and RT-qPCR analysis was performed. Functional ER pathway activity was assessed by a computational Bayesian model inferring ER signaling pathway activity from mRNA levels of ER-specific target genes. RESULTS: Our analysis of 29 HGSCs shows that neither total percentage of ER protein expression, nor ER histoscores are significantly correlated to ER signaling pathway activity (respectively, p = 0.473 and p = 0.606). Classification of HGSC into three groups based on ER histoscores 0-100 (n = 6), 101-200 (n = 15) and 201-300 (n = 8) resulted in comparable mean ER signaling pathway activity among the groups (p = 0.356). Several samples in the higher ER histoscore groups had low ER signaling pathway activity, indicating that nuclear ER protein expression is not sufficient to describe transcriptional ER activation. CONCLUSION: Positive immunohistochemical ER staining is not always indicative of an active ER signaling pathway and is, therefore, a poor predictor of anti-estrogen response. Further research is needed to prove the predictive value of ER signaling pathway activity regarding anti-estrogen sensitivity in HGSC patients.