|Year : 2018 | Volume
| Issue : 9 | Page : 494-498
The expression of insulin receptor substrate 1 and estrogen receptor as prognostic factor on breast cancer patient
Hyun Goo Kim1, Sang Uk Woo1, Hoon Yub Kim1, Gil Soo Son1, Jae Bok Lee1, Jeong Won Bae1, Ok Hee Woo2, Dae Sik Yang3, Jae Hong Seo4, Ae-Ree Kim5
1 Department of Surgery, Korea University, Seoul, South Korea
2 Department of Diagnostic Radiology, Korea University, Seoul, South Korea
3 Department of Radiation Oncology, Korea University, Seoul, South Korea
4 Department of Internal Medicine, Korea University, Seoul, South Korea
5 Department of Pathology, Korea University, Seoul, South Korea
|Date of Web Publication||29-Jun-2018|
Sang Uk Woo
Department of Surgery, Korea University, Guro Hospital, 97 Gurodong-Gil, Guro-Ku, Seoul
Source of Support: None, Conflict of Interest: None
Background: Insulin receptor substrate 1 (IRS-1) has been known to be an associated factor with breast cancer progression. However, there has been little study with respect to the relationship between the expression of IRS-1 and breast cancer prognosis in clinical practice. In this study, we evaluated the impact of the estrogen receptor (ER) and IRS-1 on the recurrence and survival of breast cancer patients.
Methods: We analyzed the pathologic finding of 376 tissue samples from breast cancer patients who received proper treatment between January 1990 and December 2006 using the tissue microarray. We measured the expression of ER and IRS-1 by immunohistochemistry staining and analyzed the difference of recurrence and survival rate in each subgroup of ER and IRS-1.
Results: Our results show that there is a significant difference of disease-free survival (DFS) according to ER and IRS-1 subgroups with both univariate and multivariate analyses. Specifically, ER-positive and IRS-1-positive breast cancer samples showed improved DFS compared to ER-positive and IRS-1-negative breast cancer (adjusted hazard ratio: 2.17; 95% confidence interval: 1.15–4.09; P = 0.01). There was a difference of overall survival according to ER and IRS-1 subgroups by univariate analysis (P = 0.01), but not by multivariate analysis (P = 0.36).
Conclusion: ER and IRS-1 subgroups appear to be critical factors for the prediction of breast cancer recurrence. In particular, we suggest that the patients who have ER-positive and IRS-1-negative breast cancer undergo more aggressive treatment because they have poorer prognoses.
Keywords: Breast cancer, estrogen receptor, insulin receptor substrate 1
|How to cite this article:|
Kim HG, Woo SU, Kim HY, Son GS, Lee JB, Bae JW, Woo OH, Yang DS, Seo JH, Kim AR. The expression of insulin receptor substrate 1 and estrogen receptor as prognostic factor on breast cancer patient. J Can Res Ther 2018;14, Suppl S2:494-8
|How to cite this URL:|
Kim HG, Woo SU, Kim HY, Son GS, Lee JB, Bae JW, Woo OH, Yang DS, Seo JH, Kim AR. The expression of insulin receptor substrate 1 and estrogen receptor as prognostic factor on breast cancer patient. J Can Res Ther [serial online] 2018 [cited 2019 Jul 19];14:494-8. Available from: http://www.cancerjournal.net/text.asp?2018/14/9/494/181180
| > Introduction|| |
Recently, many growth factors and proteins have been studied as prognostic factors of recurrence and survival in breast cancer. Among them, studies of insulin-like growth factor (IGF) and insulin receptor substrate (IRS) have received attention. IRS is known to be a key protein in the IGF pathway that mediates cell proliferation, migration, and survival., Among various IRS subtypes, IRS-1 and IRS-2 are the main subtypes in breast cancer. In previous studies, IRS-1 has been shown to be a factor in the progression of breast cancer., The expression of IRS-1 may be associated with a hormone receptor: IRS-1 expression was increased in estrogen receptor (ER) positive and well-differentiated breast cancer cells. A study has shown a significant reduced relapse-free survival and overall survival (OS) in progesterone receptor (PR) positive and IRS-1-positive cancer cells, suggesting that the effect of IRS-1 on survival is different in response to the existence of hormone receptors.
The role of IRS-1 in breast cancer prognosis is still debated. Some studies reported that IRS-1 levels correlate with poor prognosis, whereas others have announced that IRS-1 is associated with a good prognosis., The purpose of this study was to investigate the impact of the expression of ER and IRS-1 on the recurrence and survival of breast cancer patients.
| > Methods|| |
The surgical samples of breast cancer were selected from the tissue bank of Korea University Guro Hospital, which had been previously collected with the Institutional Ethics Committee's approval (KUGH12181-001). We retrospectively reviewed tissue samples from 376 breast cancer patients who underwent optimal operations for breast cancer between January 1992 and December 2006. Based on the patients' medical records, we investigated the age, histological grade, stage, recurrence, and death of the patients.
Construction of tissue microarray (TMA) using tissue block and immunohistochemical staining was performed by one pathologist and read by two pathologists. For immunohistochemical staining, serial 4 μm sections of TMA were mounted on electrostatic slides, heat dried at 56°C for 30 min, deparaffinized in xylene, and rehydrated with graded ethanol. The slides were incubated in 3% hydrogen peroxidase in methanol for 15 min to block endogenous peroxidase activity. The slides were then incubated in 0.3% bovine serum albumin/×1 tris-buffered saline (TBS) for 20 min to reduce on specific background staining. An anti-IRS1 antibody (1 mg/ml, polyclonal, Abcam, Ab52167, Cambridge, UK) was applied for 30 min at room temperature as the primary antibody. After a series of TBS washings, bound antibody was detected with a polymer secondary antibody (Dako, Carpinteria, CA, USA). Slides were counterstained with hematoxylin and eosin.
The immunohistochemical staining was assessed in a semi-quantitative method. Cancer cells with nuclear staining of the ER and PR expression were considered to be immunoreactive and scored. Evaluation of hormone receptor expression was based on the Allred scoring method. To examine the expression of HER2, membrane staining was evaluated according to the guidelines of the American Society of Clinical Oncology/College of American Pathologists. Cases with a score of 3+ were considered to be HER2-positive. Cases with a score of 2+ were evaluated for HER2 gene amplification status with silver-enhanced in situ hybridization. The process of staining for ER, PR, HER2, CK5/6, epidermal growth factor receptor (EGFR), and Ki-67 was completely automated using the Ventana Benchmark Autostainer (Ventana Medical systems, Tucson, AZ, USA).
According to the degree of IRS-1 expression, we classified the IRS-1 expression as follows: 0, none; 1+, weak; 2+, moderate; and 3+, strong [Figure 1]. We considered IRS-1 expressions more than 2+ to be positive.
|Figure 1: Insulin receptor substrate 1 expression in breast cancer tissue (a) Negative (b) weak (c) moderate (d) strong expression|
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We classified the samples into four subgroups: (ER(+)/IRS-1(+); ER(+)/IRS-1(−); ER(−)/IRS-1(−); and ER(−)/IRS-1(+)), according to the expression of ER and IRS-1 and analyzed each group for its correlation with recurrence and survival.
Statistical evaluation was performed using SPSS Statistics version 20 (IBM Corporation, Armonk, NY, USA). Comparison of the clinicopathological parameters according to the expression of IRS-1 was assessed using the Chi-square test for trends. Recurrence-free survival and disease-free survival (DFS) were estimated with the Kaplan–Meier test. We analyzed the correlation between variables and survival using the log-rank test for univariate analysis. The Cox proportional-hazards model was used to identify factors associated with an increased risk of recurrence and death. Significant factors in univariate analysis were entered in the multivariate model, and nonsignificant factors were removed by means of a backward selection procedure. A P < 0.05 was considered statistically significant in all data analyses.
| > Results|| |
We analyzed a total of 376 patients, with a median age of 45 years and median tumor size of 2.5 cm. During the median follow-up time of 79.5 months, the overall recurrence of breast cancer was 30.6% and the OS was 79.3%. Patient demographics and clinicopathological characteristics are listed in [Table 1]. According to the expression of ER and IRS-1, the number of cases that were ER(+)/IRS-1(+), ER(+)/IRS-1(−), ER(−)/IRS(−), and ER(−)/IRS(+) were 80 (21.3%), 158 (42.0%), 88 (23.4%), and 50 (13.3%), respectively.
|Table 1: Demographics and clinicopathological characteristics of 376 patients|
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[Table 2] represents the correlations of IRS-1 expression with the clinicopathological parameters. Only Ki67 status was associated with IRS-1 expression (P < 0.001), but the other parameters did not show any correlations with IRS-1 expression.
|Table 2: Correlation between IRS-1 expression and other clinicopathological characteristics|
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In univariate analysis, there were significant differences with respect to DFS in age, TNM stage, EGFR expression, neoadjuvant chemotherapy, adjuvant chemotherapy, and ER/IRS-1 subgroups. In particular, patients with ER(+)/IRS-1(+) had a longer DFS compared to the other ER/IRS-1 subgroups (P = 0.014) [Figure 2]. In multivariate Cox regression analysis, the ER/IRS subgroups, such as TMN stage and neoadjuvant chemotherapy, were independent prognostic factors for DFS (P = 0.048). Similar to the univariate analysis, the ER(+)/IRS-1(+) subgroup showed the best DFS among the ER/IRS-1 subgroups, and the ER(−)/IRS-1(+) subgroup was associated with a significant decrease in DFS compared to the ER(+)/IRS-1(+) subgroup (hazard ratio [HR] =2.57; 95% confidence interval [CI]: 1.18–5.60; P = 0.017) [Table 3]. Interestingly, the ER(+)/IRS-1(−) subgroup showed poorer DFS in comparison with the ER(+)/IRS-1(+) subgroup (HR = 2.17; 95% CI: 1.15-4.09; P = 0.016) [Table 3].
|Figure 2: Disease-free survival (a) and overall survival (b) curves for patients according to estrogen receptor (ER)/insulin receptor substrate-1 (IRS-1) subgroups|
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|Table 3: Univariate and multivariate analysis of recurrence by clinicopathologic parameters|
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Similar to DFS, the univariate analysis of OS showed that patients with ER(+)/IRS-1(+) had significantly better prognoses than other subgroups (P = 0.012) [Figure 3], although the ER/IRS-1 subgroups were not significantly associated with OS in multivariate analyses. Separately, patients with ER(−)/IRS(+) were associated with poorer OS compared to patients with ER(+)/IRS(+) (HR = 3.03; 95% CI: 1.06–8.64; P = 0.037) [Table 4].
|Figure 3: Overall survival curves for patients according to ER/IRS-1 subgroups|
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|Table 4: Univariate and multivariate analysis of survival by clinicopathologic parameters|
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| > Discussion|| |
IRS protein is a family of cytoplasmic proteins that transmit various signals from the insulin receptors and IGF-I receptors to trigger cellular responses. In particular, IRS-1 protein is known to be an important element of signaling pathways in mammary cells. Many studies have reported that IRS-1 proteins play a significant role in cell metabolism, motility, survival, and proliferation,, and this mechanism has also been shown in breast tumor cells.
In breast cancer, IRS-1 overexpression is correlated with ER expression, and many studies have reported that IRS-1 protein is a central component of ER/IGF-1 crosstalk., Since 1995, numerous reports have demonstrated the relationship between ER and IRS in breast cancer cell lines, but most of them were in vitro studies.,, There were a few authors who found that IRS-1 overexpression could influence the prognosis of breast cancer patients., However, they had divergent views on whether IRS-1 overexpression represented a good or poor prognosis.
In this study, we demonstrated that the ER/IRS-1 subgroups are independent prognostic factors in the recurrence of breast cancer. Interestingly, the ER(+)/IRS-1(+) subgroup showed a significantly better DFS than the ER(+)/IRS-1(−) subgroup. However, there is no difference with respect to DFS in the ER(−)/IRS-1(+) subgroup compared to the ER(−)/IRS-1(−) subgroup (data were not shown, odds ratio = 1.50; 95% CI: 0.83–2.72; P = 0.171). These results suggest that IRS-1 overexpression might have a different function according to ER expression in breast cancer. Migliaccio et al. found similar results that the PR-positive and IRS-1-positive breast cancer showed a better recurrence-free and OS although the results were shown only in tamoxifen-treated patients. Bartucci et al. suggested that IRS-1 related IGF-1 pathways showed different functions in ER-positive and ER-negative breast cancer cells. Such studies and our results indicate that we should reconsider the ER/IRS-1 subgroups, not IRS-1 alone, as prognostic factors.
Our results revealed that IRS-1 overexpression in ER-positive breast cancer related to a lower recurrence. However, there is a controversy about whether IRS-1 overexpression results in a better or worse prognosis. Various studies have demonstrated that IRS-1 overexpression in breast cancer is associated with reduced DFS and good prognosis.,, An in vitro study  reported that IRS-1 suppression promoted breast cancer metastasis and supports in that it found IRS-1 is a good prognostic factor. On the contrary, some authors have found that IRS-1 expression correlates with poorly differentiated carcinoma and lymph node metastasis., Recently, a study showed that treatment of anti-IRS-1 siRNA enhanced the cytotoxic effects of tamoxifen. However, these studies have limitations; most of them were in vitro studies and did not consider other prognostic factors (i.e., TMN stage, tumor grade, adjuvant chemotherapy, and hormone therapy). We emphasize that the ER/IRS-1 subgroups in this study showed excellent results in breast cancer recurrence even after adjusting for other clinicopathological variables.
There are some limitations to our study. First, the number of patients in this study is too small to be meaningfully divided into the four subgroups. Second, there may be a bias that TMA is not equal to the whole breast cancer tissue.
| > Conclusion|| |
The ER and IRS-1 subgroups appear to be a critical factor for the prediction of breast cancer recurrence. In particular, we suggest that the patients who have ER-positive and IRS-1-negative breast cancer undergo more aggressive treatment such as those with ER-negative breast cancer. More specific studies are necessary to determine the role of IRS-1 according to ER status.
Financial support and sponsorship
This work was supported by a Korea University Grant (k0931331).
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3], [Table 4]