Details for: CL0000076

Cell ID: CL0000076

Cell Name: squamous epithelial cell

Description: An epithelial cell that has a flattened morphology.

Selected Context(s): Overall

Gene Significance Landscape

Display Options
Score:
Display
Genes

Contexts:

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 squamous epithelial cell 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 squamous epithelial cell. 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 squamous epithelial cell. 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 squamous epithelial cell. 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.

Maximum number of selected genes.
Select a context for the baseline cell.
Select a context for the target cell.
Target Cell for CSI:  squamous epithelial cell (CL0000076)

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

Loading network (please wait)...

## Summary A [squamous epithelial cell](/details-cell/CL0000076) is a terminally differentiated epithelial cell characterized by its flattened, scale-like morphology. Based on gene significance analysis, this cell type is defined by a unique transcriptional and metabolic state geared towards structural integrity, high metabolic activity, and interaction with the immune system. The high **Overall** expression specificity (CSI Z-score) of genes involved in polyamine metabolism, such as [SAT1](/details-gene/6303), and cytoskeletal components, including multiple myosin light chains, suggests these functions are central to establishing and maintaining the squamous epithelial identity. Furthermore, the prominence of the epithelial-specific transcription factor [ELF3](/details-gene/1999) and components of the antigen presentation machinery ([B2M](/details-gene/567)) underscores its defined lineage and role as a sentinel cell at barrier surfaces. ## Key Characteristics and Function Analysis of gene expression specificity provides a multi-faceted view of the [squamous epithelial cell's](/details-cell/CL0000076) core functions. These can be grouped into several key biological themes. * **Epithelial Lineage and Transcriptional Identity:** The high significance of the E74-like ETS transcription factor 3 ([ELF3](/details-gene/1999)) (PRS: 97.8%) strongly confirms the cell's epithelial identity. [ELF3](/details-gene/1999) is a master regulator known to control the expression of genes crucial for epithelial cell differentiation and function ([Link](https://pubmed.ncbi.nlm.nih.gov/9234700/)). This is complemented by the high specificity of [KRT8](/details-gene/3856), a type II cytokeratin, which is a fundamental component of the intermediate filament cytoskeleton in simple epithelia. * **Structural Integrity and Cytoskeletal Dynamics:** A defining feature is the specific expression of a suite of genes related to the cytoskeleton. Multiple non-muscle myosin light chains, including [MYL6](/details-gene/4637), [MYL12A](/details-gene/10627), and [MYL12B](/details-gene/103910), are top markers. This suggests that actomyosin contractility is not just a housekeeping function but a specialized activity, likely critical for maintaining cell shape, managing mechanical stress at tissue barriers, and potentially cell migration during wound healing. * **Specialized Metabolism and Stress Response:** The top-ranked gene by expression specificity is [SAT1](/details-gene/6303), spermidine/spermine N1-acetyltransferase. This enzyme is the rate-limiting step in polyamine catabolism, a pathway essential for cell growth, proliferation, and apoptosis ([Link](https://pubmed.ncbi.nlm.nih.gov/1985966/)). Its status as the most specific marker suggests that the precise regulation of intracellular polyamine levels is a critical and defining characteristic of these cells. Additionally, the high significance of Glutathione S-Transferase Pi 1 ([GSTP1](/details-gene/2950)) indicates a robust capacity for detoxification and managing oxidative stress, a vital function for cells forming a barrier to the external environment. * **Immune Surveillance and Antigen Presentation:** The high specificity scores for Beta-2-Microglobulin ([B2M](/details-gene/567)) and HLA class I histocompatibility antigen, E alpha chain ([HLA E](/details-gene/3133)) highlight a significant role in immune communication. As a core component of all MHC class I molecules, the high specificity of [B2M](/details-gene/567) indicates that [squamous epithelial cells](/details-cell/CL0000076) are well-equipped to present endogenous antigens to cytotoxic T lymphocytes, enabling immune surveillance against viral infections and malignant transformation. * **Anti-Markers:** The lack of specific enrichment for numerous heterogeneous nuclear ribonucleoproteins (e.g., [HNRNPA1](/details-gene/3178), [HNRNPC](/details-gene/3183)) and components of core mitochondrial bioenergetics ([UQCRB](/details-gene/7381), [SLC25A6](/details-gene/293)) is noteworthy. This does not imply these functions are absent; rather, it suggests that the expression of these ubiquitous "housekeeping" genes is not uniquely distinguishing for [squamous epithelial cells](/details-cell/CL0000076) compared to other cell types. The cell's identity is therefore defined less by the baseline cellular machinery and more by the specialized structural, metabolic, and immune-facing programs highlighted by the top markers. ## Clinical Significance and Contextual Roles Although this analysis is performed in an **Overall** context without a direct disease comparison, the key markers for [squamous epithelial cells](/details-cell/CL0000076) have significant clinical implications, particularly in oncology and immunology. The top marker, [SAT1](/details-gene/6303), and its regulation of polyamines are frequently dysregulated in cancer, where altered polyamine metabolism can drive uncontrolled proliferation. Its high specificity in normal squamous epithelium suggests that changes in its expression could be a sensitive indicator of early malignant changes leading to squamous cell carcinoma. Similarly, the transcription factor [ELF3](/details-gene/1999) has been identified as an oncogene in certain contexts, with its overexpression linked to tumorigenesis ([Link](https://pubmed.ncbi.nlm.nih.gov/9129154/)). The prominent signature of antigen presentation machinery ([B2M](/details-gene/567)) is critical for cancer immunosurveillance. Loss of [B2M](/details-gene/567) expression is a known mechanism of immune escape in various cancers, allowing tumor cells to evade detection by T cells. Therefore, the high baseline specificity of [B2M](/details-gene/567) in healthy [squamous epithelial cells](/details-cell/CL0000076) provides a reference point for identifying pathological immune evasion in squamous cell carcinomas. Furthermore, the high specificity of [GSTP1](/details-gene/2950), a detoxification enzyme, may have implications for therapy. Overexpression of [GSTP1](/details-gene/2950) in tumors can contribute to chemotherapy resistance by metabolizing and inactivating cytotoxic drugs. Understanding its baseline expression in the cell of origin is crucial for developing effective treatment strategies. ## Potential Mechanisms and Research Directions 1. **Hypothesis: Polyamine flux is a primary determinant of squamous epithelial cell fate and function.** * **Surprising Findings:** The emergence of a metabolic enzyme, [SAT1](/details-gene/6303), as the single most specific gene marker is unexpected. It outranks canonical structural proteins (keratins) and lineage-defining transcription factors. This suggests that the dynamic control of polyamine catabolism is a more unique and defining feature of this cell's biology than its static structure. * **Testable Questions:** How does targeted inhibition or overexpression of [SAT1](/details-gene/6303) impact the terminal differentiation program and barrier formation in a 3D organotypic model of human epidermis? Does [SAT1](/details-gene/6303) activity change in response to proliferative signals (e.g., growth factors) versus differentiation signals (e.g., high calcium)? 2. **Hypothesis: Actomyosin contractility is functionally linked to the immune sentinel function of squamous epithelial cells.** * **Surprising Findings:** The concurrent high specificity of multiple non-muscle myosin light chains ([MYL6](/details-gene/4637), [MYL12A](/details-gene/10627), [MYL12B](/details-gene/103910]) alongside key antigen presentation molecules ([B2M](/details-gene/567)) suggests a non-canonical linkage. This may indicate that cellular mechanics, such as tension and shape, directly influence the efficiency of immune surveillance at barrier tissues. * **Testable Questions:** Does mechanical stress (e.g., stretching) on cultured [squamous epithelial cells](/details-cell/CL0000076) lead to changes in the surface expression or clustering of MHC class I complexes? Can the disruption of the actomyosin cytoskeleton with drugs like blebbistatin alter the cell's ability to present viral or tumor antigens to co-cultured T cells?