Analysis of Increased EGFR and IGF-1R Signaling and Its Correlation with Socio-Epidemiological Features and Biological Profile in Breast Cancer Patients: A Study in Northern Brazil

Abstract

Introduction: Breast cancer (BC) is the second most frequent cancer worldwide. It is known that a subset of BC has amplification, and overexpression of the epidermal growth factor receptor (EGFR) and high expression of the insulin-like growth factor receptor-1 (IGF-1R) are correlated with a favorable prognosis. This study aimed to evaluate the prognostic and predictive values of the EGFR and IGF-1R in tumor samples from patients with BC and their correlation with socio-epidemiological features.

Patients and methods: We analyzed socio-epidemiological, clinical-pathological data and tumor tissues from 124 patients with BC undergoing treatment, to assess levels of EGFR and IGF-1R mRNA and protein. The predictive performance included the calculation of area-under-the-curve (AUC) to discriminate groups of patients with high and low mRNA expression associated with survival analysis within each molecular group of BC.

Results: We found a significant expression increase (p <0.001) in EGFR associated with body mass index, angiolymphatic invasion, compromised lymph nodes and follow-up in 58.1% of the triple-negative and HER overexpression tumors. The increase in IGF-IR was significant (p <0.001) in 41.9% of luminal tumors A and B. ROC analysis showed that EGFR had a higher predictive performance (AUC = 0.891) than IGF-1R (AUC = 0.60). The Kaplan-Meier analysis indicated that only the high expression of EGFR was associated with a decreased probability of survival for patients, what did not happen with IGF-1R.

Conclusion: Our results suggest that EGFR and IGF-1R expression patterns associated with the clinical characteristics of patients and biological profile influenced the evolution of BC.

Keywords: EGFR; IGF-IR; breast cancer; hormonal receptors; predictive performance.

Figure 1

Levels of gene expression of EGFR and IGF-1R in socio-epidemiological and pathological–clinical data. Variations in levels of gene expression were significant (p <0.001) for EGFR (A) BMI, (C) angiolymphatic invasion and (E) compromised lymph nodes. IGF-1R did not show statistical significance (B) BMI, (D) angiolymphatic invasion and (F) compromised lymph nodes. In all graphs, the expression of breast tumors was normalized by non-neoplastic breast tissue. The dotted lines represent the 1.5-fold-change.

Figure 2

Levels of gene expression of EGFR and IGF-1R in the follow-up variables and biological profiles. The increase in gene expression levels was significant (p <0.001) for EGFR (A) only at follow-up. IGF-1R (B) did not show statistical significance. The increase in gene expression levels was significant (p <0.001) for EGFR (C) in the triple-negative and Her overexpressed negative receptors, whereas IGF-1R (D) was higher in the positive receptors, Luminal A and Luminal B. In all graphs, the expression of breast tumors was normalized by non-neoplastic breast tissue. The dotted lines represent the 1.5-fold-change.

Figure 3

(A and B) Box Plot shows average levels of normalized expression of mRNA and proteins from EGFR and IGF-1R. The boxes are drawn from the 75th to the 25th percentile. The vertical lines above and below the box define the maximum and minimum values and the dots indicate outliers, the horizontal line inside the box representing the median. Kruskal–Wallis test (p <0.0001) was applied to compare the means between the four groups. In all graphs, expression in breast tumors was normalized by the non-malignant tissue removed from reduction mammoplasty. RQ: relative quantification; (T) tumor sample; (N) normal non-malignant tissue; The whiskers indicate the minimum and maximum values. The dotted lines represent the 1.5-fold-change. (C) Donut Chart shows the ranking of the positions of the biological profiles. (D and E) The heat map shows an expression profile defined by the unsupervised cluster to group by the similarity of gene expression the samples of profile RE negative and RE positive, respectively. Z-score was the metric applied to infer the best grouping between profiles. Gradients with a red color trend represent profiles with a lower Z-score and gradients with a blue color tendency with a higher Z-score. (ns, not significant, ****p < 0.0001).

Figure 4

(A) Analysis of the ROC curve to separate patients into groups of high and low expression of EGFR and IGF-1R associated with follow-up. The largest area was for the EGFR receptor, AUC = 0.891 which represents a cut-off point of 1.5 from normalized expression. The IGF-1R receiver had a smaller area AUC = 0.60 for a cut-off point of 1.5. (B) and (C) Kaplan–Meier analysis of the overall survival in months of patients with breast cancer as a function of the expression of the EGFR and IGF-1R receptors. The high gene expression ≥1.5 (blue line) for the two EGFR receptors as opposed to the low expression (yellow line), is strongly associated with a lower probability of survival for patients who do not express hormone receptors in one year after treatment. The low gene expression of IGF-1R was shown to be associated with the lower probability of survival of patients. ROC, receiver operating characteristic. Log-rank p-value <0.0001.