Estrogen receptor, a marker for human breast cancer differentiation and patient prognosis

A web-based novel model for predicting prognostic value in patients with invasive micropapillary carcinoma in breast cancer: a real-world data retrospective cohort study

Invasive micropapillary carcinoma (IMPC) accounts for less than 2% of all invasive breast cancers and usually associates with poor survival, so we investigated the prognostic factors for IMPC using a large population-based database and designed a web-based novel model. Clinicopathological prognostic factors were evaluated using the Surveillance, Epidemiology, and End Results (SEER) database. Multivariate Cox regression analysis was performed to evaluate the prognostic value of variables on the overall survival. A web-based nomogram was finally constructed to predict the survival probability. The model was validated in an external dataset. A web-based model, combined with age, radiation, clinical stage, and hormone receptor (HR) immunochemistry status four prognostic factors, was constructed. The C-index (0.714, 95% CI 0.683-0.741), calibration curves, and decision curves showed that this model was superior in prediction. By determining the cut-off values, high-risk group and low-risk group were divided. The Kaplan-Meier survival curves showed that these two groups had significantly different survival rates (P < 0.0001). The result of C-index, calibration curves, and Kaplan-Meier survival curves were consistent in the validation cohort. The novel nomogram with four risk factors resulted in accurate prognostic prediction for IMPC.

Nomogram predicting overall prognosis for invasive micropapillary carcinoma of the breast: a SEER-based population study

OBJECTIVES

The prognosis of invasive micropapillary carcinoma (IMPC) of the breast is determined by many clinicopathological factors. This study aims to identify prognostic factors and develop reliable nomogram to predict the overall survival (OS) in patients with IMPC.

DESIGN

Log-rank test and Cox proportional hazards analysis were used to identify variables and construct a nomogram based on the training cohort. C-index and calibration curves were performed to evaluate the performance of the model in the training cohort and validation cohorts.

SETTING

We collected the patient data from the Surveillance, Epidemiology and End Results (SEER) database. This database holds data related to the cancer incidence from 18 population-based cancer registries in the USA.

PARTICIPANTS

The SEER database was used to screen 754 eligible patients as the study cohort. The whole cohort was randomly divided into a training cohort (n=377) and a validation cohort (n=377).

RESULTS

Age at diagnosis, hormone receptors, number of positive regional lymph nodes and clinical stage were independent prognostic factors for patients with IMPC. The calibration curves presented excellent consistency between the actual and nomogram-predict survival probabilities in the training and validation cohorts. The C-index values of the nomogram were 0.794 and 0.774 for OS in the training and validation cohorts, respectively.

CONCLUSIONS

The novel nomogram provides new insights of the risk of each prognostic factor and can assist doctors in predicting the 1-year, 3-year and 5-year OS in patients with IMPC.

Prognosis of lymphotropic invasive micropapillary breast carcinoma analyzed by using data from the National Cancer Database

Background

Invasive micropapillary carcinoma (IMPC) is an uncommon subtype of breast cancer. Previous studies of this subtype demonstrated a higher propensity for lymph node metastases as compared with invasive ductal carcinoma (IDC). The purpose of the present study was to determine the clinical characteristics, outcomes, and propensity for lymph node metastasis of patients with IMPC of the breast recorded in the National Cancer Database (NCDB).

Methods

Records of patients with IMPC diagnosed between 2004 and 2014 were retrieved from the NCDB. Log-rank test was performed to evaluate associations of clinical characteristics with overall survival (OS). Cox proportional hazards model was used to determine variables associated with OS.

Results

Overall, 2660 patients with IMPC met the selection criteria; the 5-year OS rate was 87.5% and 24.9% of patients had nodal involvement at presentation. Patients with ≥ 4 positive lymph nodes had shorter OS than node-negative patients, whereas patients with 1–3 positive nodes had similar OS to node-negative patients. Age < 65 years, receipt of radiotherapy, and estrogen receptor positivity were also associated with prolonged OS. The benefit of radiotherapy was limited to IMPC patients undergoing lumpectomy; there was no benefit for the patients undergoing mastectomy (regardless of nodal positivity/negativity).

Conclusions

Favorable prognostic factors of IMPC patients included age < 65 years, < 4 positive lymph nodes, receipt of radiotherapy, and estrogen receptor positivity. The results presented herein suggest a survival benefit associated with radiotherapy in IMPC treatment, though this may be limited to the patients treated with lumpectomy.

Characterization of patient-derived tumor xenografts (PDXs) as models for estrogen receptor positive (ER+HER2- and ER+HER2+) breast cancers

The research was to appraise the utility of the patient-derived tumor xenografts (PDXs) as models of estrogen receptor positive (ER+HER2- and ER+HER2+) breast cancers. We compared protein expression profiles by Reverse Phase Protein Array (RPPA) in tumors that resulted in PDXs compared to those that did not. Our overall PDX intake rate for ER+ breast cancer was 9% (9/97). The intake rate for ER+HER2+ tumors (3/16, 19%) was higher than for ER+HER2- tumors (6/81, 7%). Heat map analyses of RPPA data showed that ER+HER2- tumors were divided into 2 groups by luminal A/B signature [protein expression of ER, AR, Bcl-2, Bim (BCL2L11), GATA3 and INPP4b], and this expression signature was also associated with the rate of PDX intake. Cell survival pathways such as the PI3K/AKT signaling and RAS/ERK pathways were more activated in the specimens that could be established as PDX in both classes. Expression of the ER protein itself may have a bearing on the potential success of an ER+ PDX model. In addition, HER2 and its downstream protein expressions were up-regulated in the ER+HER2+ patient tumors that were successfully established as PDX models. Moreover, the comparison of RPPA data between original and PDX tumors suggested that the selection/adaptation process required to grow the tumors in mice is unavoidable for generation of ER+ PDX models, and we identified differences between patient tumor samples and paired PDX tumors. A better understanding of the biological characteristics of ER+PDX would be the key to using PDX models in assessing treatment strategies in a preclinical setting.

Automated measurement of estrogen receptor in breast cancer: a comparison of fluorescent and chromogenic methods of measurement

Whereas FDA-approved methods of assessment of estrogen receptor (ER) are 'fit for purpose', they represent a 30-year-old technology. New quantitative methods, both chromogenic and fluorescent, have been developed and studies have shown that these methods increase the accuracy of assessment of ER. Here, we compare three methods of ER detection and assessment on two retrospective tissue microarray (TMA) cohorts of breast cancer patients: estimates of percent nuclei positive by pathologists and by Aperio's nuclear algorithm (standard chromogenic immunostaining), and immunofluorescence as quantified with the automated quantitative analysis (AQUA) method of quantitative immunofluorescence (QIF). Reproducibility was excellent (R(2)>0.95) between users for both automated analysis methods, and the Aperio and QIF scoring results were also highly correlated, despite the different detection systems. The subjective readings show lower levels of reproducibility and a discontinuous, bimodal distribution of scores not seen by either mechanized method. Kaplan-Meier analysis of 10-year disease-free survival was significant for each method (Pathologist, P=0.0019; Aperio, P=0.0053, AQUA, P=0.0026); however, there were discrepancies in patient classification in 19 out of 233 cases analyzed. Out of these, 11 were visually positive by both chromogenic and fluorescent detection. In 10 cases, the Aperio nuclear algorithm labeled the nuclei as negative; in 1 case, the AQUA score was just under the cutoff for positivity (determined by an Index TMA). In contrast, 8 out of 19 discrepant cases had clear nuclear positivity by fluorescence that was unable to be visualized by chromogenic detection, perhaps because of low positivity masked by the hematoxylin counterstain. These results demonstrate that automated systems enable objective, precise quantification of ER. Furthermore, immunofluorescence detection offers the additional advantage of a signal that cannot be masked by a counterstaining agent. These data support the usage of automated methods for measurement of this and other biomarkers that may be used in companion diagnostic tests.

Overexpression of ligase defective E6-associated protein, E6-AP, results in mammary tumorigenesis

E6-associated protein (E6-AP) is a dual function protein. It acts as an E3 ubiquitin-protein ligase enzyme and coactivator of steroid hormone receptors such as estrogen (ERα) and progesterone (PR) receptors. It promotes the degradation of ERα and PR through the ubiquitin-proteasome pathway. Furthermore, it has been shown that the levels of E6-AP are inversely associated with that of ERα in human breast tumors. But the role of wild-type human E6-AP and its ubiquitin-protein ligase activity in mammary tumorigenesis is still unknown. To investigate this role, the authors utilized transgenic mice lines that specifically overexpress either the wild-type human E6-AP (E6-AP(WT)) or the ubiquitin-protein ligase defective E6-AP that contains C833S mutation (E6-AP(C833S)) in the mammary gland. To further substantiate the role of E6-AP in the development of breast tumorigenesis, it was also examined the expression of E6-AP in a large cohort of human breast cancer samples. The transgenic mice that overexpress wild-type E6-AP (E6-AP(WT)) fail to develop mammary tumors. Unlike the E6-AP(WT) mice, the E6-AP(C833S) mice that overexpress ubiquitin-protein ligase defective E6-AP protein develop mammary hyperplasia with a median latency of 18 months. These observations suggest that the inactivation of the ubiquitin-protein ligase function of E6-AP is sufficient to initiate the process of mammary tumor development. Furthermore, the data also suggests that E6-AP exerts its effects on target cells by modulating the protein levels and functions of ERα and PR. In addition, it was found in human breast cancer patients that the level of E6-AP is decreased in invasive breast tumors compared to normal breast tissue. Moreover, the authors also show that the survival patterns for E6-AP negative patients were worse compared to E6-AP positive patients. Taken together, these data suggests that E6-AP may act as a tumor suppressor in breast.

Automated subcellular localization and quantification of protein expression in tissue microarrays

The recent development of tissue microarrays-composed of hundreds of tissue sections from different tumors arrayed on a single glass slide-facilitates rapid evaluation of large-scale outcome studies. Realization of this potential depends on the ability to rapidly and precisely quantify the protein expression within each tissue spot. We have developed a set of algorithms that allow the rapid, automated, continuous and quantitative analysis of tissue microarrays, including the separation of tumor from stromal elements and the sub-cellular localization of signals. Validation studies using estrogen receptor in breast carcinoma show that automated analysis matches or exceeds the results of conventional pathologist-based scoring. Automated analysis and sub-cellular localization of beta-catenin in colon cancer identifies two novel, prognostically significant tumor subsets, not detected by traditional pathologist-based scoring. Development of automated analysis technology empowers tissue microarrays for use in discovery-type experiments (more typical of cDNA microarrays), with the added advantage of inclusion of long-term demographic and patient outcome information.

The prognostic significance of the monoclonal antibody III D 5 to human milk fat globule antigen in breast cancer

The monoclonal antibody III D 5 identifies an antigen in human milk fat globule membrane, found also on breast epithelial cells. Immunohistochemistry with the antibody was used in the staining of formalin-fixed, paraffin-embedded sections of 80 breast carcinomas. The duration of follow-up of patients was from seven to twelve years. The presence or absence of metastases in regional lymph nodes at the time of primary operation, histological grade and necrosis of tumours correlated highly significantly to the survival of patients. The patients whose tumours exhibited positive staining with the antibody III D 5 had an improved survival-rate compared with those with III D 5 negative tumours. In the patients without metastases at the time of primary operation, the histological grade of primary tumour had only a weak correlation with survival, while the same patients with III D 5 positive tumours had significantly better prognosis compared to the III D 5 negative cases. Inclusion of the III D 5 immunoreactivity with other factors in a prognostic index could permit a more accurate estimation of prognosis in patients with mammary carcinoma.

Discrepancy in ER levels of breast carcinoma in biopsy vs mastectomy specimens

The presence of estrogen receptors (ER) in breast tumors has been used by many as the major indicator for hormonal treatment of breast cancer. However, multiple factors have been shown to be involved in determining the hormone dependence of breast cancer. This paper reports another factor that influences the accuracy of ER determination. From January 1977 through December 1983 fifty-eight (58) of these patients had ER determination of both biopsy and mastectomy specimens. Of the 31 patients that remained ER positive in mastectomy specimen, 13 had significantly lower ER levels (by at least 50%) from the mastectomy specimens. These findings indicate that ER status is greatly influenced by the source of the specimen.

The effect of molybdate on the intracellular distribution of estrogen receptor in mammary tumors

The addition of sodium molybdate (20 mM) to human breast tumor homogenates results in an increased yield of estrogen receptor sites in the cytosol, but reduces the number of sites detectable in salt extracts of purified nuclei. Only about 25% of the increase in cytosol receptor can be accounted for by the loss of nuclear sites. Addition of molybdate to isolated nuclear salt extracts has no inhibitory effect on the estrogen receptor assay, but addition of the oxyanion to the cytosol after separation of the initial nuclear pellet still gives a significant increase in estradiol binding capacity. Furthermore, addition of molybdate to the suspension from the first nuclear pellet still results in loss of binding sites in the nuclear salt extract. This rules out the possibility that the negative effect of molybdate on nuclear receptor recovery is by its inhibition of cytosol receptor activation and translocation during tissue preparation. The number of nuclei isolated from estrogen receptor-containing tumors does not differ significantly in the presence or absence of molybdate. Estrogen receptor-negative tumors however yield fewer nuclei, particularly when they are processed in the presence of molybdate. We conclude that when homogenization of tumors is carried out in the presence of molybdate, a significant fraction of estrogen receptor which would normally be present in purified nuclei is lost, perhaps by leakage through the nuclear membrane.