Serum human epidermal growth factor receptor 2 levels as a real-time marker for tumor burden in breast cancer patients

Glycosylated proteins with abnormal glycosylation changes are potential biomarkers for early diagnosis of breast cancer

Conventional cancer management relies on tumor type and stage for diagnosis and treatment, which leads to recurrence and metastasis and death in young women. Early detection of proteins in the serum aids diagnosis, progression, and clinical outcomes, possibly improving survival rate of breast cancer patients. In this review, we provided an insight into the influence of aberrant glycosylation on breast cancer development and progression. Examined literatures revealed that mechanisms underlying glycosylation moieties alteration could enhance early detection, monitoring, and therapeutic efficacy in breast cancer patients. This would serve as a guide for the development of new serum biomarkers with higher sensitivity and specificity, providing possible serological biomarkers for breast cancer diagnosis, progression, and treatment.

Breast Cancer-Epidemiology, Risk Factors, Classification, Prognostic Markers, and Current Treatment Strategies-An Updated Review

Simple Summary

Breast cancer is the most common cancer among women. It is estimated that 2.3 million new cases of BC are diagnosed globally each year. Based on mRNA gene expression levels, BC can be divided into molecular subtypes that provide insights into new treatment strategies and patient stratifications that impact the management of BC patients. This review addresses the overview on the BC epidemiology, risk factors, classification with an emphasis on molecular types, prognostic biomarkers, as well as possible treatment modalities.

Abstract

Breast cancer (BC) is the most frequently diagnosed cancer in women worldwide with more than 2 million new cases in 2020. Its incidence and death rates have increased over the last three decades due to the change in risk factor profiles, better cancer registration, and cancer detection. The number of risk factors of BC is significant and includes both the modifiable factors and non-modifiable factors. Currently, about 80% of patients with BC are individuals aged >50. Survival depends on both stage and molecular subtype. Invasive BCs comprise wide spectrum tumors that show a variation concerning their clinical presentation, behavior, and morphology. Based on mRNA gene expression levels, BC can be divided into molecular subtypes (Luminal A, Luminal B, HER2-enriched, and basal-like). The molecular subtypes provide insights into new treatment strategies and patient stratifications that impact the management of BC patients. The eighth edition of TNM classification outlines a new staging system for BC that, in addition to anatomical features, acknowledges biological factors. Treatment of breast cancer is complex and involves a combination of different modalities including surgery, radiotherapy, chemotherapy, hormonal therapy, or biological therapies delivered in diverse sequences.

Breast cancer stem cells in HER2-negative breast cancer cells contribute to HER2-mediated radioresistance and molecular subtype conversion: clinical implications for serum HER2 in recurrent HER2-negative breast cancer

Although it has been proposed that the beneficial effect of HER2-targeted therapy in HER2-negative breast cancer is associated with the molecular subtype conversion, the underlying mechanism and the clinical biomarkers are unclear. Our study showed that breast cancer stem cells (BCSCs) mediated HER2 subtype conversion and radioresistance in HER2-negative breast cancer cells and evaluated serum HER2 as a clinical biomarker for HER2 subtype conversion. We found that the CD44⁺/CD24^–/low BCSCs from HER2-negative breast cancer MCF7 cells overexpressed HER2 and EGFR and showed the radioresistant phenotype. In addition, we showed that trastuzumab treatment sensitized the radioresistant phenotype of the CD44⁺/CD24^–/low cells with decreased levels of HER2 and EGFR, which suggested that HER2-targeted therapy in HER2-negative breast cancer could be useful for targeting BCSCs that overexpress HER2/EGFR. Importantly, our clinical data showed that serial serum HER2 measurement synchronously reflected the disease relapse and the change in tumor burden in some patients who were initially diagnosed as HER2-negative breast cancer, which indicated that serum HER2 could be a clinical biomarker for the evaluation of HER2 subtype conversion in patients with recurrent HER2-negative breast cancer. Therefore, our data have provided in vitro and in vivo evidence for the molecular subtype conversion of HER2-negative breast cancer.

Predictive value of serum HER2 ECD in patients with HER2-positive advanced gastric cancer treated with trastuzumab plus chemotherapy

BACKGROUND

The levels of serum HER2 extracellular domain (ECD) are highly correlated with tissue HER2 status in metastatic gastric cancer (AGC). We sought to explore whether serum HER2 ECD could predict the efficacy of trastuzumab-treated HER2-positive AGC.

MATERIALS AND METHODS

From 2011 to 2013, trastuzumab-treated AGC patients were enrolled. Serum HER2 ECD was centrally measured by chemiluminescence immunoassays (CLIA) method in available samples at baseline and after two cycles of trastuzumab combined with chemotherapy. The correlation between serum HER2 ECD and overall response rate (ORR) and progression-free survival (PFS) was analyzed.

RESULTS

Sixty-five patients were analyzed with a median age of 58 years (range, 27-80 years). A significant difference of serum HER2 ECD levels was found between patients with HER2 IHC 3+ and those with HER2 IHC 2+ and FISH positive (p = 0.014). There was a significantly better ORR (80.00 vs. 50.00 %, p = 0.017) and PFS (median PFS, 268 vs. 139 days, p = 0.039) for patients with abnormal baseline serum HER2 ECD than for patients with normal serum HER2 ECD. Change in serum HER2 ECD during chemotherapy was significantly correlated with response to chemotherapy (79.17 vs. 51.52 %, p = 0.033) and PFS (median PFS, 303 vs. 147 days, p = 0.005) in patients with HER2-positive tumor tissue.

CONCLUSIONS

Our results support the clinical utility of measuring serum HER2 ECD levels in patients with advanced gastric cancer. Baseline and early changes in serum HER2 ECD could be useful for monitoring clinical outcome in HER2-positive AGC patients receiving trastuzumab-combined chemotherapy.