Relationship of estrogen and progesterone receptors to clinical outcome in metastatic endometrial carcinoma: a Gynecologic Oncology Group Study.
BACKGROUND
The goal of this study was to explore the relationship between the expression of hormone receptors in metastatic endometrial tumors and clinical response to daily tamoxifen citrate and intermittent weekly medroxyprogesterone acetate.


METHODS
Patients with measurable recurrent or advanced endometrial cancer were enrolled on a clinical trial, Gynecologic Oncology Group Study 119. A pretreatment tumor biopsy was obtained and subjected to immunohistochemical analyses. Estrogen receptor-alpha (ER-alpha) and progesterone receptor (PR) were assessed on frozen tissues, and PR isoforms A and B were detected on fixed tissues. The receptors were scored using a semi-quantitative HSCORE, with a cut off greater than 75 considered positive.


RESULTS
Of the 60 eligible patients, 45 had evaluable tissues for all receptors. For ER, 40% of the cases were positive; for PR, 45% were positive. The sub-cellular distribution of PRA was exclusively nuclear, and 16% of the tumors demonstrated positive staining. PRB was nuclear and cytoplasmic, with 22% of the tumors staining for nuclear PRB and 36% of the tumors staining for cytoplasmic PRB. ER and PR from frozen tissues and PRA and cytoplasmic PRB from fixed tissues significantly decreased with increasing tumor grade. The co-expression of ER-alpha with PR from the frozen tissues (r=0.68, p<0.001) and PRA (r=0.58, p<0.001) from the fixed tissues was statistically significant. The ER HSCORE was related to both response and overall survival; there was no statistically significant correlation of PR with clinical response in this small number of patients.


CONCLUSIONS
ER-alpha measured in metastatic endometrial carcinoma tissue prior to hormonal therapy was statistically significantly related to clinical response to daily tamoxifen and intermittent medroxyprogesterone acetate.
Singh
Meenakshi
M
Department of Pathology, The University of Colorado Health Sciences Center, Denver, CO 80262, United States.
Zaino
Richard J
RJ
Filiaci
Virginia J
VJ
Leslie
Kimberly K
KK
D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D016889:Endometrial Neoplasms / Q000188:drug therapy* / Q000378:metabolism* / Q000473:pathology; D047628:Estrogen Receptor alpha / Q000096:biosynthesis*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017258:Medroxyprogesterone Acetate / Q000008:administration & dosage; D009367:Neoplasm Staging; D011446:Prospective Studies; D011980:Receptors, Progesterone / Q000096:biosynthesis*; D013629:Tamoxifen / Q000008:administration & dosage; D016896:Treatment Outcome
D047628:Estrogen Receptor alpha; D011980:Receptors, Progesterone; D013629:Tamoxifen; D017258:Medroxyprogesterone Acetate