Clinicopathological and prognostic value of CD24 expression in breast cancer: a meta-analysis

Associations of Early-Life and Adult Anthropometric Measures with the Expression of Stem Cell Markers CD44, CD24, and ALDH1A1 in Women with Benign Breast Biopsies

BACKGROUND

According to the stem cell hypothesis, breast carcinogenesis may be related to the breast stem cell pool size. However, little is known about associations of breast cancer risk factors, such as anthropometric measures, with the expression of stem cell markers in noncancerous breast tissue.

METHODS

The analysis included 414 women with biopsy-confirmed benign breast disease in the Nurses' Health Study and Nurses' Health Study II. Birthweight, weight at age 18, current weight, and current height were reported via self-administered questionnaires. IHC staining of stem cell markers (CD44, CD24, and aldehyde dehydrogenase family 1 member A1) in histopathologically normal epithelial and stromal breast tissue was quantified using an automated computational image analysis system. Linear regression was used to examine the associations of early-life and adult anthropometric measures with log-transformed stem cell marker expression, adjusting for potential confounders.

RESULTS

Birthweight [≥10.0 vs. <5.5 lbs: β (95% confidence interval) = 4.29 (1.02, 7.56); P trend = 0.001 in the stroma] and adult height [≥67.0 vs. <63.0 inch: 0.86 (0.14, 1.58); P trend = 0.02 in the epithelium and stroma combined] were positively associated with CD44 expression. Childhood body fatness was inversely associated (P trend = 0.03) whereas adult height was positively associated with CD24 expression in combined stroma and epithelium (P trend = 0.03).

CONCLUSIONS

Our data suggest that anthropometric measures, such as birthweight, adult height, and childhood body fatness, may be associated with the stem cell expression among women with benign breast disease.

IMPACT

Anthropometric measures, such as birthweight, height, and childhood body fatness, may have long-term impacts on stem cell population in the breast.

Identification of potential immunotherapy biomarkers for breast cancer by bioinformatics analysis

Breast cancer is a serious malignancy with a high incidence worldwide and a tendency to relapse. We used integrated bioinformatics analysis to identify potential biomarkers in breast carcinoma in the present study. Microarray data, 127breast tumor samples and 23 non-tumor samples, received from the Gene Expression Omnibus (GEO) dataset; 121 differentially expressed genes (DEGs) were selected. Functional analysis using DAVID revealed that these DEGs were highly gathered in endodermal cell differentiation and proteinaceous extracellular matrix. Five bioactive compounds (prostaglandin J2, tanespimycin, semustine, 5182598, and flunarizine) were identified using Connectivity Map. We used Cytoscape software and STRING dataset to structure a protein–protein interaction (PPI) network. The expression of CD24, MMP1, SDC1, and SPP1 was much higher in breast carcinoma tissue than in Para cancerous tissues analyzed by Gene Expression Profiling Interactive Analysis (GEPIA) and ONCOMINE. Overexpression ofCD24, MMP1, SDC1, and SPP1 indicated the poor prognosis in breast carcinoma patients analyzed by Kaplan–Meier (KM) Plotter. Immunohistochemistry microarray was used to further confirm that protein expression of CD24, MMP1, SDC1, and SPP1 was much higher in tumor sections than in Para cancerous tissues. Hub genes expression at the protein level was correlated tothe breast cancer subtype and grade. Furthermore, immunity analysis showed that CD24, MMP1, SDC1, and SPP1 were potentially associated with five immune cell types infiltration (CD8+ T cells, CD4+ T cells, neutrophils, macrophages,and dendritic cells) by TIMER. Thus, this study indicates potential biomarkers that could have applications in the development of immune therapy for breast cancer. However, further studies are required for verifying these results in vivo and vitro.

Glycosylation Modulates Plasma Membrane Trafficking of CD24 in Breast Cancer Cells

In breast cancer, expression of Cluster of Differentiation 24 (CD24), a small GPI-anchored glycoprotein at the cell periphery, is associated with metastasis and immune escape, while its absence is associated with tumor-initiating capacity. Since the mechanism of CD24 sorting is unknown, we investigated the role of glycosylation in the subcellular localization of CD24. Expression and localization of wild type N36- and/or N52-mutated CD24 were analyzed using immunofluorescence in luminal (MCF-7) and basal B (MDA-MB-231 and Hs578T) breast cancer cells lines, as well as HEK293T cells. Endogenous and exogenously expressed wild type and mutated CD24 were found localized at the plasma membrane and the cytoplasm, but not the nucleoplasm. The cell lines showed different kinetics for the sorting of CD24 through the secretory/endocytic pathway. N-glycosylation, especially at N52, and its processing in the Golgi were critical for the sorting and expression of CD24 at the plasma membrane of HEK293T and basal B type cells, but not of MCF-7 cells. In conclusion, our study highlights the contribution of N-glycosylation for the subcellular localization of CD24. Aberrant N-glycosylation at N52 of CD24 could account for the lack of CD24 expression at the cell surface of basal B breast cancer cells.