Steroid receptors, HER2/neu and Ki-67, in endometrioid type of endometrial carcinoma: Correlation with conventional histomorphological features of prognosis

Impact of Hormone Receptor Status and Ki-67 Expression on Disease-Free Survival in Patients Affected by High-risk Endometrial Cancer

Objectives

The aim of this study was to evaluate the immunohistochemical (IHC) expression of Ki-67, estrogen receptors α (ERsα), and progesterone receptors (PRs) in high-risk endometrial cancer patients and to assess their prognostic impact.

Methods/Materials

Immunohistochemical expression of Ki-67, ERsα, and PRs was evaluated in primary untreated endometrial cancer. The correlation among IHC staining and risk factors of recurrence such as age, Federation International of Gynecology and Obstetrics stage, grading, depth of invasion, and metastatic spread was assessed.

Results

Eighty-two patients were available for the analysis. Mean ± SD age was 65.05 ± 10.48 years. The IHC assessment revealed a lack of ERα in 46.3% and of PR in 48.7% as well as a high Ki-67 in 31.7%. Loss of ERα and PR was associated with a significant higher rate of advanced stage of disease, a higher frequency of G3 tumors, and a myometrial invasion greater than 50%. A strong Ki-67 expression correlated with a deeper myometrial invasion. Analysis of the interrelationship between receptor immunonegativity revealed a relevant association of ERα immunolocalization with PR and with a high Ki-67 expression. The present study also showed that loss of ERα (P = 0.003), advanced Federation International of Gynecology and Obstetrics stage (P < 0.001), and high Ki-67 (P = 0.004) were independent prognostic factors of a shorter disease-free survival. Importantly, loss of ERα, loss of PR, and a high Ki-67 were correlated with a higher incidence of distant recurrence.

Conclusions

A systematic immunohistochemistry should be a key step in the therapeutic algorithm and could contribute to the identification of high-risk tumors.

Minichromosome maintenance complex component 6 (MCM6) expression correlates with histological grade and survival in endometrioid endometrial adenocarcinoma

Minichromosome maintenance complex component 6 (MCM6) is involved in initiating DNA replication and is upregulated during licensed G0 phase of the cell cycle. This early expression permits its labeling of more proliferating cells than those by Ki-67. Here using a cohort of 89 endometrioid adenocarcinoma, we report findings made on the prognostic value of MCM6 based on immunohistochemical labeling index (LI) of the protein in comparison with that of Ki67 as no such information is currently available. Additionally, we examined the prognostic values of these markers based on their mRNA expression using a cohort of uterine corpus endometrial carcinoma (UCEC, n = 307) taken from The Cancer Genome Atlas (TCGA) database. Our evidence indicated the presence of a positive correlation between the LI of MCM6 and the histological grade of endometrioid endometrial adenocarcinoma (grade I, 66.7%; grade II, 75.3%; grade III, 81.4%; p < 0.001) and an inverse correlation between the LI of MCM6 and the overall and progression-free survival (p = 0.02 for both). The LI of Ki-67 correlated with grade (p < 0.001), but not survival. The MCM6 and Ki-67 inter-observer intra-class correlation coefficients were excellent: 0.84 (95% confidence interval, 0.83-0.91) and 0.84 (0.77-0.90), respectively. For in silico analyses of the TCGA cohort, both univariate and multivariate Cox analyses (p = 0.003 and p = 0.03, respectively) revealed high MCM6 mRNA Z-scores associated with reduced overall survival. This association was absent for Ki-67. MCM6 is thus a highly reproducible marker of poor prognosis in endometrial cancer. Evaluation of MCM6 should thus be considered in daily practice for risk stratification.

Molecular profiling of estrogen receptor α and progesterone receptor transcript variants in endometrial cancer

The human genes coding for estrogen receptor alpha (ERα) and progesterone receptor (PR) express multiple receptor splice variants. Some of these receptor variants previously have been shown to exert distinct functions in cancer cells and might therefore differentially affect individual prognosis or therapy response. To examine the role of ERα- and PR-isoforms in endometrial cancer, we compared the expression of 19 ERα transcripts and 15 PR mRNA isoforms in human endometrium and in endometrioid endometrial cancer. Expression of seven ERα splice variants, total PR and of five PR transcript isoforms was found to be significantly decreased in endometrial cancer. In endometrioid G3 tumors, expression of 17 ERα and 10 PR splice variants was reduced when compared to normal tissue. Notably, only 13% of G3 tumors did not express any ERα variant and only in 25% of G3 samples no PR transcripts were expressed. Seven splice variants were preferentially expressed in G1 and G2 tumors. In G1 tumors, a higher number of different ERα and PR splice variants was expressed than in normal endometrium, G2 or G3 tumors. Expression of total PR and of single PR splice variants was found to be positively associated with PTEN. Our results encourage further studies to elucidate to what extent the heterogeneous co-expression profiles we found in endometrial cancer patients differentially affect both individual prognosis and therapy response.

Expression of SCUBE2 gene declines in high grade endometrial cancer and associates with expression of steroid hormone receptors and tumor suppressor PTEN

SCUBE2 (Signal peptide-CUB-epidermal growth factor-like domain-containing 2) gene codes for a cell-surface glycoprotein. In breast cancer, SCUBE2 transcript levels are part of important prognostic and predictive gene signatures and are linked to expression of estrogen receptor α (ERα). To elucidate the role of this gene in endometrial cancer, we compared SCUBE2 expression in malignant and normal endometrial tissue specimens. We then examined its correlation with steroid hormone receptors and PTEN and compared it to SCUBE2 expression in breast cancer samples. Expression of SCUBE2 was found to be decreased in G3 endometrial cancer when compared to postmenopausal endometrium or to G1 tumors (p < 0.05). In postmenopausal endometrium, SCUBE2 transcript levels were more than twice as high as in premenopausal women. In breast cancer, SCUBE2 expression was found to be notably reduced particularly in ERα-negative G3 tumors. Both in endometrial and breast cancer we observed a significant positive correlation of SCUBE2 transcript levels with expression of ERα, PR and PTEN. Our data suggest that SCUBE2, like in breast cancer, associates with ERα and might have a potential as prognostic or predictive marker in endometrial cancer.

A phase II evaluation of gefitinib in the treatment of persistent or recurrent endometrial cancer: a Gynecologic Oncology Group study

BACKGROUND

A phase II trial was performed to evaluate the efficacy and safety of gefitinib in patients with persistent/recurrent endometrial cancer.

METHODS

Women with histologically confirmed persistent/recurrent endometrial cancer were treated with 500mg oral gefitinib daily until progression or severe toxicity, with progression-free survival (PFS) at six months as the primary endpoint. Tumor expression of total epidermal growth factor receptor (EGFR), estrogen receptor (ER), progesterone receptor A (PRA) and B (PRB), Ki67, pEGFR and activated extracellular signal-regulated kinase (pERK) were examined pre- and post-treatment. EGFR was sequenced, and serum concentrations of soluble EGFR (sEGFR) at baseline also were examined.

RESULTS

Of 29 patients enrolled, 26 were evaluable for efficacy and toxicity. Four patients experienced PFS ≥6 months, and one had a complete response which was not associated with an EGFR mutation. The concentration of sEGFR in pretreatment serum was positively correlated with overall survival (OS), but not with responsiveness to gefitinib in this small patient cohort. Expression of tumor biomarkers was not associated with PFS or OS. Co-expression of ER with PRA in primary and recurrent tumors, and pEGFR with pERK in primary tumors was observed.

CONCLUSIONS

This treatment regimen was tolerable but lacked sufficient efficacy to warrant further evaluation in this setting. The possible association between serum sEGFR concentrations and OS, and temporal changes in expression of pEGFR and pERK and the documented CR of one patient are interesting and warrant additional investigation.

The expression ratios of estrogen receptor α (ERα) to estrogen receptor β1 (ERβ1) and ERα to ERβ2 identify poor clinical outcome in endometrioid endometrial cancer

The prognostic relevance of estrogen (ER) and progesterone receptor (PR) expression in endometrioid endometrial cancer is still controversially discussed. The present study has focused on the evaluation of the prognostic value of ERα, ERβ1, ERβ2, and PR in this histotype. Specifically, we were interested in evaluating whether the relative level of ER subtype-specific expression (in terms of a ratio ERα/ERβ1 and ERα/ERβ2) would predict clinical outcome better than their absolute levels in patients with endometrioid endometrial cancer. To this end, protein content was assessed by immunohistochemistry in a group of 121 cases and staining was analyzed in relation to clinicopathologic variables, disease-free survival and overall survival. Results obtained have demonstrated that none of the biological markers analyzed possess an independent prognostic role with regard to disease-free survival. Multivariate analysis of overall survival has shown that ERα alone is not an independent prognostic indicator in patients with endometrioid endometrial cancer (hazard ratio [HR]; 0.5; 95% confidence interval [CI], 0.09-3.0; P = .5). On the other hand, an ERα/ERβ1 ratio of 1 or less or an ERα/ERβ2 ratio of 1 or less has proved to be independently associated with a higher risk of death (HR, 6.4 [95% CI, 1.0-40.6; P = .04] and 9.7 [95% CI, 1.1-85.3; P = .04], respectively) along with age, tumor stage, and Ki-67. In conclusion, we report here that the ERα/ERβ1 and ERα/ERβ2 expression ratios are independent prognostic markers of survival in endometrioid endometrial cancer; these findings suggest that phenotyping these interacting markers conjointly may better predict patient survival than each individual marker alone.

Expression of cysteine protease cathepsin L is increased in endometrial cancer and correlates with expression of growth regulatory genes

Proteases contribute to tumor invasion and metastasis by degrading basement membranes and extracellular matrix (ECM). In this study, we compared gene expression levels of two proteases, cysteine protease Cathepsin L2 (CTSL2) and matrix metalloproteinase MMP11, in human endometrium and endometrial cancer. Our data demonstrate CTSL2 transcript levels to be strongly elevated in endometrial cancer, particularly in G3 tumors. Furthermore, we observed a highly significant positive correlation of CTSL2 with expression of growth regulatory genes Ki-67, cyclin B1, MYBL2, p21/WAF, and HER2 receptor tyrosine kinase. Our data suggest that CTSL2 might be involved in progression of endometrial cancer.

Icb-1 Gene expression is elevated in human endometrial adenocarcinoma and is closely associated with HER2 expression

Human gene icb-1 (C1orf38) has been initially cloned by our group from endometrial adenocarcinoma cells. In this study, we examined icb-1 expression in 90 endometrial cancer and normal endometrial tissue specimens. Expression of icb-1 was significantly (about 3.5-fold) higher in endometrial cancer than in normal endometrium (p <.0001). Determination of various molecular markers revealed that only Ki-67 expression differed between both groups in a similarly significant manner. Furthermore, we observed a highly significant positive correlation of icb-1 transcript levels with c-erbB2 (HER2) expression (p <.0001). Our data strongly encourage further studies on the function of icb-1 in endometrial cancer.