Here is a detailed overview of the EPHB3 gene, incorporating your requests for additional information:

### EPHB3 Gene Overview
- **Gene Symbol**: EPHB3
- **Location**: Human Chromosome 3 (3q11.2)
- **Gene Type**: Protein-coding gene
- **Function**: EPHB3 encodes a receptor tyrosine kinase that interacts with ephrin-B family ligands, facilitating bidirectional signaling between neighboring cells. It plays a critical role in several developmental processes, particularly in the nervous system, including axon guidance, dendritic spine development, and cell migration.

### Associated Genes
Beyond EPHB2, which has an overlapping and redundant function, EPHB3 may be associated with several other genes involved in similar or related processes, such as:
- **EFNB2**: The ephrin-B family ligand that interacts with EPHB3.
- **CRB3**: Involved in maintaining the epithelial integrity during development.
- **SHC1**: A signaling adaptor that may transduce signals following EPHB3 activation.
- **PTK2 (FAK)**: Involved in signaling pathways downstream of EPHB3, especially regarding cell adhesion and migration.
- **Rho family genes (e.g., RHOA)**: Involved in cytoskeletal reorganization downstream of Eph receptor signaling.
  
### Aging and Age-related Diseases
Research on the EPHB3 gene's role in aging or age-related diseases is less extensive than for other genes; however, a few relevant points include:
- **Neurodegenerative Diseases**: Changes in ephrin/Eph signaling have been linked to aging and neurodegenerative conditions like Alzheimer's disease. Dysregulation of EPHB3 may influence synaptic plasticity and neuron survival.
- **Cancer**: Abnormal EPHB3 signaling pathways may contribute to tumor progression and metastasis in various cancers, particularly by affecting cell migration and adhesion during cancer cell invasion.

### Drug Interactions
Currently, there are no specific drugs directly targeting EPHB3 mentioned in the literature. However, certain classes of drugs may indirectly influence the pathways related to EPHB3:
- **Tyrosine Kinase Inhibitors (TKIs)**: Drugs targeting other receptor tyrosine kinases might affect EPHB3 signaling as part of broader cellular signaling modifications.
- **Neurotrophic factors**: Molecules such as BDNF (Brain-Derived Neurotrophic Factor) may impact EPHB3-related signaling pathways influencing neuronal survival and repair but are not direct interactants.

### Pathways and Biological Processes
EPHB3 is involved in several key biological pathways and processes, including but not limited to:
- **Axon Guidance**: Guiding neural connections during development.
- **Dendritic Spine Development**: Contributing to excitatory synapse formation and plasticity.
- **Cell Migration and Adhesion**: Involved in processes such as angiogenesis (formation of new blood vessels) and the development of structures, such as the palate and thymic epithelium.
- **Wnt Signaling Pathway**: EPHB3 may play a role in transducing Wnt signals, influencing cell fate decisions.
- **Synaptic Plasticity**: Regulating synaptic efficiency and memory functions in the brain.
- **Intestinal Epithelium Differentiation**: Helping to maintain the balance between progenitor and differentiated cell populations.

Overall, EPHB3 is a critical modulator in the intricate signaling networks necessary for proper development, neural functioning, and potential links to pathology in aging and disease. Further studies may elucidate its specific roles in these contexts.