The **ARID4A** gene (AT-rich interactive domain-containing protein 4A) encodes a protein with significant roles in transcriptional regulation and epigenetic modifications. Here’s a detailed account of the ARID4A gene, including your requests:

### 1. Associated Genes
ARID4A is primarily known for its associations with several other genes and proteins that are critical for transcriptional regulation and cellular function:
- **RB1 (Retinoblastoma 1)**: ARID4A directly interacts with this protein, which is essential for cell cycle regulation.
- **ARID4B**: This gene is often mentioned in association with ARID4A, particularly in the context of spermatogenesis and transcriptional regulation.
- **HDACs (Histone Deacetylases)**: While not specifically a single gene, ARID4A recruits HDACs as part of its function in transcriptional repression.

Additionally, ARID4A may interact with transcription factors such as:
- **Androgen Receptor (AR)**: It enhances the expression of genes required for sperm maturation in conjunction with ARID4B.
- **SIN3A (mSin3A)**: An important co-repressor involved in transcriptional repression.

### 2. Association with Aging and Age-Related Diseases
While specific studies directly linking ARID4A to aging or age-related diseases are limited, it is associated with processes that could impact aging:
- **Stem Cell Maintenance and Differentiation**: Dysregulation of genes like ARID4A can influence processes critical for the maintenance of stem cells and their differentiation, potentially impacting aging.
- **Hematopoiesis**: Given its role in regulating genes involved in hematopoiesis, abnormalities could contribute to age-related hematological disorders.
- **Cancer**: As noted, ARID4A may function as a leukemia suppressor, implicating it in cancer pathways that are often altered with aging.

### 3. Drug Interactions
While there’s limited information specifically pertaining to drugs interacting with ARID4A, certain classes of drugs are known to affect histone modifications and transcriptional repression, which might indirectly affect ARID4A's functions:
- **Histone Deacetylase Inhibitors (HDACi)**: These drugs are designed to inhibit the activity of HDACs, potentially impacting the recruitment or function of ARID4A in transcriptional regulation.
- **Targeted Cancer Therapies**: Treatments that aim at transcriptional regulation or those targeting pathways involving ARID4A may be relevant, considering its role in tumor suppression.

### 4. Pathways and Biological Processes
ARID4A is involved in several important biological pathways, including:
- **Cell Cycle Regulation**: Modulating the activity of RB1, ARID4A plays a significant role in cell cycle progression.
- **Transcriptional Repression**: Acting as a co-repressor, ARID4A is involved in the repression of genes critical for processes such as development and differentiation.
- **Histone Modification**: It plays a role in regulating histone methylation, which is critical for gene expression and chromatin structure.
- **Spermatogenesis**: Directly involved in the transcriptional activation of genes necessary for sperm maturation.
- **Hematopeiesis**: Regulates genes involved in blood cell formation and may influence immune responses through its activities in the bone marrow.

### Conclusion
ARID4A is a multifaceted gene with implications in transcriptional regulation, spermatogenesis, and possibly in aging and cancer. Understanding its interactions and roles in various pathways continues to be a subject of research, providing insights into its significance in cellular biology and disease mechanisms.