Expression of BCRP/ABCG2 Protein in Invasive Breast Cancer and Response to Neoadjuvant Chemotherapy.

BACKGROUND: Breast cancer resistance protein (BCRP), or ATP-binding cassette subfamily G member 2 (ABCG2), is an ATP-binding cassette (ABC) transporter that mediates energy-dependent transport of substrate drugs out of the cell. Its overexpression may contribute to intrinsic drug resistance in vitro. However, the current literature has not yet clarified the clinical significance of BCRP/ABCG2 in invasive breast carcinoma. OBJECTIVES: The purpose of this study was to validate the expression of BCRP/ABCG2 in invasive breast carcinoma and its role in response to neoadjuvant chemotherapy. METHODS: In this study, a pretherapeutic core biopsy was performed in 222 patients. BCRP/ABCG2 expression in carcinoma tissue was measured by immunohistochemistry. BCRP/ABCG2 expression correlations with clinicopathological features, molecular subtypes, and therapy response after neoadjuvant chemotherapy were investigated. RESULTS: The results showed that BCRP/ABCG2 was expressed in different molecular subtypes. The proportions of patients with high BCRP/ABCG2 expression were similar in luminal A and luminal B tumors (luminal B, 80%; luminal A, 78%), compared with other molecular subtypes (triple-negative, 63%; HER2+, 58%, p = 0.05). BCRP/ABCG2 expression and the number of lymphatic metastases (p = 0.001) and tumor size (p = 0.011) demonstrated a statistically significant correlation. Low BCRP/ABCG2 expression was associated with an increased pathological complete response (pCR) rate of 38%, higher than the 19% in tumors with high BCRP/ABCG2 expression (p = 0.002). In multivariable analysis, BCRP/ABCG2 and hormone receptor (HR) expression were identified as independent risk factors of pCR (p = 0.003 and p = 0.013, respectively). CONCLUSIONS: BCRP/ABCG2 is highly expressed in HR-positive breast cancer. High BCRP/ABCG2 expression is associated with lymphatic metastasis, tumor size, and poor pCR. BCRP/ABCG2 may be a novel potential biomarker that can predict clinical progression and therapy response after neoadjuvant chemotherapy.

Prognostic Value of LRG1 in Breast Cancer: A Retrospective Study.

BACKGROUND: High expression of leucine-rich alpha-2-glycoprotein 1 (LRG1) is closely related to angiogenesis, which may play an important role in promoting invasion and metastasis. However, the current literature has yet to clarify the clinical significance of LRG1 in breast cancer. OBJECTIVES: The purpose of this work was to validate the correlation between LRG1 expression and prognosis in early breast cancer. METHODS: We utilized an LRG1 detection agent in 330 cases of early breast cancer. The correlation of LRG1 expression with clinicopathological features, patient recurrence, and survival was investigated. RESULTS: Compared with adjacent tissue samples, an elevated expression of LRG1 was observed in breast cancer samples. Moreover, LRG1 expression is associated with the number of lymphatic metastases and TNM pathological stage (p = 0.000, p = 0.000, respectively). For disease-free survival (DFS), the Kaplan-Meier curve indicated a poorer prognosis for the group with high LRG1 levels compared with the low LRG1 group (p = 0.000). A similar result was found for overall survival (OS; p = 0.000). The multivariate Cox regression indicated that LRG1 was still associated with DFS (HR 2.090, 95% CI 1.205-3.625, p = 0.009) and OS (HR 2.112, 95% CI 1.167-3.822, p = 0.013). The histological grade, TNM pathological stage, and molecular subtype were identified as independent risk factors affecting OS. CONCLUSION: In the malignant progression of breast cancer, high LRG1 levels are associated with lymphatic metastasis, histological grade, poor DFS, and poor OS. This study validates the use of LRG1 as a potential prognosis biomarker for early breast cancer.