### ITGB4 Gene Overview

**Gene Symbol:** ITGB4  
**Location:** Human Chromosome 17q25.1  
**Function:** Encodes the beta 4 subunit of integrins, which are crucial components of adhesive glycoprotein receptors involved in cell adhesion, signaling, and the maintenance of tissue architecture.

### Additional Associations with Other Genes
1. **ITGA6 (Integrin Alpha 6):** Forms a heterodimer with ITGB4, being involved in laminin binding.
2. **ERBB Receptors (e.g., ERBB2, ERBB3):** Interacts through Neuregulin-1 (NRG1) signaling pathways.
3. **IGF1 and IGF2:** Interacts with these insulin-like growth factors, playing a role in growth factor signaling pathways.
4. **Collagen Subtypes (e.g., COL7A1):** Association in the context of tissue integrity and stability.

### Aging and Age-Related Diseases
- **Skin Aging:** The expression of ITGB4 in keratinocytes is important for maintaining skin integrity. Changes in its expression may contribute to age-related decline in skin structure and barrier function.
- **Cancer Progression:** Deregulation of ITGB4 has been linked to invasive carcinoma processes, particularly in older populations where cancer rates increase.
- **Fibrosis:** Altered function of integrins, including ITGB4, can be involved in age-related fibrotic diseases, such as pulmonary fibrosis, which is more common in the elderly.

### Drug Interactions
- **Integrin Inhibitors:** Drugs targeting integrin functions, including monoclonal antibodies against integrins (e.g., natalizumab targeting α4 integrin), may affect pathways involving ITGB4.
- **Chemotherapy Agents:** Some studies suggest that integrin expression, including ITGB4, can influence the efficacy of certain chemotherapeutics, although specific drugs are not individually listed in connection to ITGB4.

### Pathways and Biological Processes
- **Hemidesmosome Assembly:** ITGB4 plays a crucial structural role in hemidesmosomes, which anchor epithelial cells to the basement membrane.
- **Cell-Matrix Adhesion:** A key player in modulating cell-matrix interactions, ITGB4 helps stabilize cells' positioning within the tissue microenvironment.
- **Signal Transduction:** Involved in pathways dependent on integrin signaling, including those related to cell cycle regulation and survival through interactions with growth factors, especially NRG1 and IGF signaling.
- **Cell Migration and Polarity Regulation:** Essential for keratinocyte motility and polarity, interactions via ITGB4 impact wound healing and tissue repair processes.

### Summary
The ITGB4 gene encodes an integrin subunit that is essential for cellular adhesion and signaling in epithelial tissues. Its associations with other genes and pathways underscore its significance in both normal physiology and pathophysiological conditions, particularly in cancer and skin integrity, which may be further influenced by aging and are of interest in therapeutic contexts.