Differential molecular pathways expression in HER2 positive early breast cancer according to hormone receptor status

Investigation of genes and pathways involved in breast cancer subtypes through gene expression meta-analysis

BACKGROUND

Molecular-based studies have revealed heterogeneity in Breast cancer BC while also improving classification and treatment. However, efforts are underway to distinguish between distinct subtypes of breast cancer. In this study, the results of several microarray studies were combined to identify genes and pathways specific to each BC subtype.

METHODS

Meta-analysis of multiple gene expression profile datasets was screened to find differentially expressed genes (DEGs) across subtypes of BC and normal breast tissue samples. Protein-protein interaction network and gene set enrichment analysis were used to identify critical genes and pathways associated with BC subtypes. The differentially expressed genes from meta-analysis was validated using an independent comprehensive breast cancer RNA-sequencing dataset obtained from the Cancer Genome Atlas (TCGA).

RESULTS

We identified 110 DEGs (13 DEGs in all and 97 DEGs in each subtype) across subtypes of BC. All subtypes had a small set of shared DEGs enriched in the Chemokine receptor bind chemokine pathway. Luminal A specific were enriched in the translational elongation process in mitochondria, and the enhanced process in luminal B subtypes was interferon-alpha/beta signaling. Cell cycle and mitotic DEGs were enriched in the basal-like group. All subtype-specific DEG genes (100%) were successfully validated for Luminal A, Luminal B, ERBB2, and Normal-like. However, the validation percentage for Basal-like group was 77.8%.

CONCLUSION

Integrating researches such as a meta-analysis of gene expression might be more effective in uncovering subtype-specific DEGs and pathways than a single-study analysis. It would be more beneficial to increase the number of studies that use matched BC subtypes along with GEO profiling approaches to reach a better result regarding DEGs and reduce probable biases. However, achieving 77.8% overlap in basal-specific genes and complete concordance in specific genes related to other subtypes can implicate the strength of our analysis for discovering the subtype-specific genes.

The impact of hormone receptor on the clinical outcomes of HER2-positive breast cancer: a population-based study

BACKGROUND

To investigate the impact of hormone receptor (HR) on the clinicopathological characteristics and prognosis of human epidermal growth factor receptor 2 (HER2)-positive breast cancer.

METHODS

Using the Surveillance, Epidemiology, and End Results database, we enrolled patients diagnosed with HER2-positive breast cancer between 2010 and 2016, which were successively assessed for eligibility and categorized into HR + /HER2 + and HR-/HER2 + subgroups. Clinicopathological characteristics were undergone comparative analyses with the baseline distinctions calibrated by propensity score matching, while the survival outcomes were compared using Kaplan-Meier method with log-rank tests.

RESULTS

A total of 46,803 HER2-positive breast cancer patients were identified, of which 32,919 individuals were HR + /HER2 + subtype and 13,884 individuals were HR-/HER2 + subtype, respectively. Comparatively, HR + /HER2 + breast cancer presented a lower histological grade, a smaller tumor size, a lower nodal involvement, and a lower rate of de novo stage IV disease. Substantial heterogeneity was detected in the metastatic patterns of organ-specific involvement between the two subgroups with initial metastasis. Overall, patients with HR + /HER2 + tumors had increasingly favorable prognosis in terms of overall survival and breast cancer-specific survival than patients with the HR-/HER2 + subtype. However, this kind of tendency exhibited disparities associated with HR-specific subtypes based on estrogen receptor (ER) and progesterone receptor (PgR) status, in which ER-/PgR + tended to present the worst prognosis.

CONCLUSION

This study revealed profound heterogeneity associated with HR status in the clinical outcomes of HER2-positive breast cancer regarding clinicopathological features, metastatic patterns, and prognosis. Prospective studies to optimize therapeutic strategies for HER2-positive subgroups are warranted.

Expressiveness of Bone Markers in Breast Cancer with Bone Metastases

INTRODUCTION

On a global scale, the malignant growth of mammary gland is the most common type of cancer in women. In the progress of mammary carcinoma, osseous metastatic invasion has a pivotal significance because it is a frequent complication occurring at an early stage of the disease.

BACKGROUND

Bone metastases in breast cancer patients lead to increased mortality and decreased health-related quality of life. Therefore, early diagnostic assessment and treatment is requested. Meanwhile the progress of the disease should be monitored closely. Regarding health-related quality of life and lifetime prolongation, osseous metastases should be early diagnosed, therapied, and monitored. Up to date the gold standard is the whole-body scintigraphy. This kind of bone imaging features has high sensitivity but shows loss of specificity.

AIM

This study aims to investigate the diagnostic versatility of bone markers in its resorption and formation function to detect bone metastases in patients with breast cancer.

PATIENTS, MATERIALS, AND METHODS

For this purpose, the concentration of competing bone processing tumor markers in serums of 78 patients was detected and analyzed. Two groups of women with mammary carcinoma with and without osseous metastases were built to examine the presence (or absence) of statistically significant disparity of tumor marker concentration. The tumor markers employed in this study were the carboxyterminal collagen type I telopeptid (CTX), known as beta-crosslaps (β-CTx), the alkaline phosphatase (AP), and its isoenzymes (especially the bone-specific AP [B-AP]). Additionally, the tumor markers for breast cancer (CA 15-3 and CEA) were analyzed in both groups.

RESULTS

Our results provide evidence that in both groups, tumor markers such as β-CTx and B-AP were a promising tool for the detection and exclusion of bone metastases in breast cancer. This comprehensive investigation shows both β-CTx and B-AP are able to fulfill the conditions of a competent appliance to detect osseous metastases of patients with mammary carcinoma.

CONCLUSION

Concerning the urgency of early and frequent detection, staging, and disease monitoring of mammary carcinoma with osseous metastases, this study renewed and underlined the importance of biochemical tumor markers - especially β-CTx and B-AP - and laid a clinical-based cornerstone to build up on a prospective research.

Gene Expression and miRNAs Profiling: Function and Regulation in Human Epidermal Growth Factor Receptor 2 (HER2)-Positive Breast Cancer

Breast cancer is the second most common cause of cancer-related deaths among women worldwide. It is a heterogeneous disease with four major molecular subtypes. One of the subtypes, human epidermal growth factor receptor 2 (HER2)-enriched (HER2-positive) is characterized by the absence of estrogen and progesterone receptors and overexpression of HER2 receptor, and accounts for 15–20% of all breast cancers. Despite the anti-HER2 and cytotoxic chemotherapy, HER2 subtype is an aggressive disease with significant mortality. Recent advances in molecular biology techniques, including gene expression profiling, proteomics, and microRNA analysis, have been extensively used to explore the underlying mechanisms behind human breast carcinogenesis and metastasis including HER2-positive breast cancer, paving the way for developing new targeted therapies. This review focuses on recent advances on gene expression and miRNA status in HER2-positive breast cancer.