Details for: CL0002324

Cell ID: CL0002324

Cell Name: basal-myoepithelial cell of mammary gland

Description: A myoepithelial cell that is part of a mammary gland and is located in the basal layer. During lactation, a basal-myoepithelial cell of mammary gland contracts under the stimulation of oxytocin. In humans, a basal-myoepithelial cell of mammary gland can be identified by high levels of CD49f and low levels of EpCAM.

Synonyms: myoepithelial cell of lactiferous gland, B-Myo cell, BM, basal cell of lactiferous duct, basal myoepithelial cell, basal, basal-myoepithelial cell, myoepithelial cell of mammary gland

Selected Context(s): Overall

Gene Significance Landscape

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Cell Significance Index (CSI) is uniquely calculated to reveal cell-specific gene markers. More info here

Significant Genes List

Genes with the highest and lowest Percentile Rank Scores (PRS) for basal-myoepithelial cell of mammary gland within the selected context(s).

Gene ID: A unique numerical identifier for this specific gene.
Symbol: Shortened abbreviation or name that represents this gene.
Ensembl Gene ID: A unique identifier assigned by Ensembl for genomic data mapping.
CSI Score: A combined effect size and statistical significance measure for basal-myoepithelial cell of mammary gland. Higher scores indicate a stronger, more significant difference in expression.
(Previously described as "Fold Change", but now represents Cliff's Delta × –log10(p).)

Gene ID: A unique numerical identifier for this specific gene.
Symbol: Shortened abbreviation or name that represents this gene.
Ensembl Gene ID: A unique identifier assigned by Ensembl for genomic data mapping.
CSI Score: A combined effect size and statistical significance measure for basal-myoepithelial cell of mammary gland. Higher scores indicate a stronger, more significant difference in expression.
Average CSI: csi sum / gene count
Cell network configuration

This network visualizes key genes for basal-myoepithelial cell of mammary gland. It primarily includes:
1. Top genes highly significant for this cell (Num. Top Cell Genes - based on the 'Min. CSI' setting).
2. Any additional specific 'Context Genes' you add below.
The final network is a combined view. Choose an Interaction Source (pathways or protein interactions) and optionally compare CSI scores with a Baseline Cell Type.

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Target Cell for CSI:  basal-myoepithelial cell of mammary gland (CL0002324)

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Node size also reflects Target Cell CSI magnitude.
Node Color (Target Cell CSI in specific network):
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 High
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 Very Low
 N/A or Not Sig.
Edges (Interactions):
 STRING (Protein-Protein)
 ONTOLOGY (Shared Pathway)
 Colors vary by pathway category; default arrow applies.

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## Summary The [basal-myoepithelial cell of mammary gland](/details-cell/CL0002324) is a specialized cell type situated in the basal layer of the mammary ductal and lobular epithelium. As its name implies, it possesses a dual character, exhibiting both epithelial and myoid (muscle-like) features. Its primary described function is the oxytocin-stimulated contraction required for milk ejection during lactation. The gene significance profile for this cell reveals that its identity is defined by a unique co-expression of genes involved in its contractile apparatus, alongside an exceptionally high and specific expression of genes related to protein translation, RNA processing, and mitochondrial energy production. This suggests that in addition to its mechanical role, the [basal-myoepithelial cell of mammary gland](/details-cell/CL0002324) functions as a highly active metabolic and biosynthetic hub, crucial for maintaining the structural and functional integrity of the mammary gland. ## Key Characteristics and Function **Overall**, the gene expression landscape of the [basal-myoepithelial cell of mammary gland](/details-cell/CL0002324) highlights three core functional pillars: a potent contractile and cytoskeletal system, high metabolic and biosynthetic activity, and a robust stress-response program. * **Contractile and Cytoskeletal Machinery:** A defining characteristic of this cell is the high expression specificity of genes encoding components of the contractile apparatus. This includes myosin light chains such as [MYL6](/details-gene/4637) (CSI: 48.88) and [MYL12B](/details-gene/103910) (CSI: 39.44), which are critical for acto-myosin-based contraction. The high significance of [CFL1](/details-gene/1072) (Cofilin 1, CSI: 37.05) further underscores a dynamic actin cytoskeleton, essential for both contraction and maintaining cell shape and adhesion within the basal layer. This molecular signature provides a strong basis for its well-established role in the physical propulsion of milk. * **High Metabolic and Translational Activity:** Perhaps the most striking feature from the data is the prominence of genes associated with fundamental cellular processes. The top marker, [TPT1](/details-gene/7178) (Translationally Controlled Tumor Protein, CSI: 48.98), along with multiple translation elongation factors ([EEF1B2](/details-gene/1933), [EEF1D](/details-gene/1936)), indicates a high capacity for protein synthesis. This is complemented by the specific expression of numerous heterogeneous nuclear ribonucleoproteins ([HNRNPA2B1](/details-gene/3181), [HNRNPA1](/details-gene/3178)) and other RNA-binding proteins ([PABPC1](/details-gene/26986), [SRP14](/details-gene/6727)), suggesting extensive post-transcriptional regulation and mRNA processing. Furthermore, a suite of mitochondrial genes involved in oxidative phosphorylation ([ND4](/details-gene/4538), [COX1](/details-gene/4512), [ND2](/details-gene/4536), [COX4I1](/details-gene/1327)) shows high specificity, pointing to a high energy demand likely required to fuel both contraction and robust biosynthesis. * **Tissue Homeostasis and Stress Response:** The specific expression of several genes involved in cellular defense and homeostasis suggests a role as a guardian of the epithelial layer. Key markers include [FTL](/details-gene/2512) (Ferritin Light Chain, CSI: 44.05), which manages iron sequestration to prevent oxidative stress, [PRDX1](/details-gene/5052) (Peroxiredoxin 1), an antioxidant enzyme, and [GSTP1](/details-gene/2950), a glutathione S-transferase involved in detoxification. The high specificity of [HMGB1](/details-gene/3146) (High Mobility Group Box 1), a protein that acts as a damage-associated molecular pattern (DAMP) when released, further implies these cells may be critical sensors and responders to tissue injury. * **Defining Anti-Markers:** The low expression specificity for genes such as [CHI3L1](/details-gene/1116) (a marker associated with inflammation and macrophage activity), [PLAU](/details-gene/5328) (urokinase, linked to tissue invasion), and [DLL1](/details-gene/28514) (a Notch ligand) helps to refine the cell's function. This profile suggests that in its basal state, the [basal-myoepithelial cell of mammary gland](/details-cell/CL0002324) is not primarily an inflammatory cell, nor is it defined by an invasive phenotype or a primary role in Notch-mediated cell-fate decisions. ## Clinical Significance and Contextual Roles While the provided data is from an **Overall** context, the specific gene markers for the [basal-myoepithelial cell of mammary gland](/details-cell/CL0002324) carry significant clinical implications, particularly in the context of breast cancer. Myoepithelial cells are known to form a critical barrier that cancer cells must breach during the transition from *in situ* to invasive carcinoma. The loss or alteration of this layer is a hallmark of cancer progression. Several of the top markers are directly implicated in cancer biology. [TPT1](/details-gene/7178), the most specific marker, is frequently overexpressed in various tumors and associated with cell proliferation and survival [Link](https://pubmed.ncbi.nlm.nih.gov/2813067/). [HMGB1](/details-gene/3146) can promote inflammation and tumor progression when released into the extracellular space [Link](https://pubmed.ncbi.nlm.nih.gov/9036861/). Conversely, [GSTP1](/details-gene/2950) often functions as a tumor suppressor and its expression is frequently lost in cancers via promoter hypermethylation [Link](https://pubmed.ncbi.nlm.nih.gov/3196325/). The high specificity of these functionally diverse, disease-relevant genes in [basal-myoepithelial cells](/details-cell/CL0002324) suggests a dual potential in breast cancer pathogenesis. In a healthy state, their robust stress-response and detoxification programs (e.g., [GSTP1](/details-gene/2950), [PRDX1](/details-gene/5052)) may actively suppress tumorigenesis. However, if these cells undergo transformation or their function is dysregulated, their high metabolic and proliferative capacity (indicated by [TPT1](/details-gene/7178) and mitochondrial activity) could potentially be co-opted to fuel tumor growth and invasion. Therefore, this cell type may represent a critical checkpoint in the development and progression of breast cancer. ## Potential Mechanisms and Research Directions 1. **Hypothesis:** Beyond its contractile function, the basal-myoepithelial cell acts as the primary metabolic and biosynthetic engine of the mammary ductal-lobular unit, providing essential energy and structural proteins to maintain the integrity of the entire epithelial bilayer. * **Surprising Findings:** The most specific gene marker for this cell, [TPT1](/details-gene/7178), is not a contractile protein but one centrally involved in regulating translation and cell growth. This suggests that the cell's biosynthetic capacity is as fundamental to its identity as its mechanical function. The high specificity of a large number of mitochondrial genes further reinforces the idea of this cell as a metabolic powerhouse. * **Testable Questions:** Does selective inhibition of mitochondrial respiration (e.g., using oligomycin) or protein synthesis (e.g., using cycloheximide) specifically in [basal-myoepithelial cells](/details-cell/CL0002324) lead to a breakdown in luminal cell polarity and viability in a 3D organoid co-culture system? 2. **Hypothesis:** Basal-myoepithelial cells function as frontline sentinels of tissue integrity, utilizing a pre-programmed, highly specific stress-response system to detect, mitigate, and signal damage, thereby acting as an intrinsic tumor-suppressive barrier. * **Surprising Findings:** The high specificity of damage-sensing molecules like [HMGB1](/details-gene/3146) and detoxification enzymes like [GSTP1](/details-gene/2950) suggests this cell is not merely a passive structural component but plays an active, protective role. This challenges the view of the myoepithelial layer as just a physical barrier, reframing it as a dynamic, chemosensory shield. * **Testable Questions:** Upon exposure to known carcinogens or oxidative stressors, do [basal-myoepithelial cells](/details-cell/CL0002324) in culture exhibit a more rapid and robust antioxidant response (e.g., upregulation of [PRDX1](/details-gene/5052) activity) compared to adjacent luminal cells, and does this response confer protection against DNA damage in the luminal population?