### EPHB4 Gene Overview

**Gene Symbol:** EPHB4  
**Gene Description:** The EPHB4 gene encodes for a member of the Eph receptor tyrosine kinase (RTK) family. These receptors are involved in mediating contact-dependent bidirectional signaling between adjacent cells through interactions with their ephrin ligands, specifically ephrin-B2. EPHB4 is crucial for various biological processes such as vascular development, heart morphogenesis, and angiogenesis.

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### 1. Genes Associated with EPHB4
While the main ligands associated with EPHB4, as mentioned, are **EFNB2**, other genes that have shown associations or interactions include:
- **VEGFA (Vascular Endothelial Growth Factor A)** – involved in angiogenesis.
- **N-cadherin (CDH2)** – plays a role in cell adhesion.
- **FGF2 (Fibroblast Growth Factor 2)** – involved in processes such as cell growth and angiogenesis.
- **PTEN (Phosphatase and Tensin Homolog)** – involved in the regulation of the cell cycle and angiogenesis.

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### 2. Association with Aging or Age-Related Diseases
EPHB4 has been implicated in several aging processes and age-related diseases:
- **Angiogenesis and Cancer:** Dysregulation of EPHB4 signaling has been linked to tumor microenvironment dynamics and cancer progression in older adults, as the ability of blood vessels to remodel becomes impaired with age.
- **Cardiovascular Diseases:** Given its role in heart morphogenesis and blood vessel function, EPHB4 is associated with age-related cardiovascular conditions, including heart failure and atherosclerosis. Age-associated changes in vascular integrity and permeability due to EPHB4 signaling may contribute to these diseases.
- **Neurodegenerative Disorders:** There is emerging evidence that EPHB4 may affect neurogenesis and synaptic plasticity. EPHB4 signaling pathways could be involved in neurodegenerative diseases, which have a higher prevalence in the aging population.

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### 3. Drug Interactions and Drug Classes
EPHB4 is a target of several therapeutic agents and experimental drugs since its role in angiogenesis and adhesion processes is critical in various pathologies. Notable drugs and classes include:
- **Tyrosine Kinase Inhibitors (TKIs):** These are researched in the context of cancers that exploit EPHB4 signaling for tumor growth and metastasis.
- **Monoclonal Antibodies:** Some antibodies targeting ephrin receptors, including those related to EPHB4, have been studied in clinical trials focusing on tumor growth inhibition.

Current drug names or classes specifically interacting with EPHB4 are not widely standardized, and research is ongoing in this area, particularly in cancer treatment.

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### 4. Pathways and Biological Processes Involved
EPHB4 is known to participate in multiple signaling pathways and biological processes:
- **Angiogenesis:** Essential for the formation of new blood vessels from pre-existing ones.
- **Cell Migration:** Involved in the movement of cells during developmental processes.
- **Cell Adhesion:** Mediates interactions between cells, which is fundamental during tissue formation.
- **Neural Development:** Plays a significant role in the development of the nervous system.
- **Heart Development:** Regulates various aspects of cardiac morphogenesis, specifically in the arrangement of endothelial cells and heart chambers.

### Conclusion
EPHB4 is a multifaceted gene with important roles in vascular development, neurogenesis, and various signaling pathways. Its associations with aging, cancer, cardiovascular diseases, and ongoing drug research emphasize its potential significance in health and disease. Further investigation is essential for understanding the full scope of its biological functions and therapeutic applications.