### SUSD2 Gene Overview

**Gene Symbol:** SUSD2  
**Location:** Plasma membrane  
**Function:** The SUSD2 gene encodes a protein involved in negatively regulating the G1/S phase transition of the cell cycle and cell division. It has been proposed as a potential cytokine receptor for GPR15LG and may function as a tumor suppressor, particularly implicated in the growth inhibition of colon cancer cells. It is also suggested to play a role in breast tumorigenesis.

### 1. Associated Genes

Aside from the previously mentioned GPR15LG, SUSD2 may have associations with the following genes:

- **TP53:** A well-known tumor suppressor involved in cell cycle regulation and apoptosis that might interact with pathways involving SUSD2.
- **KRAS:** Mutations in this gene are common in various cancers and could correlate with SUSD2's function in tumor suppression.
- **CCND1:** Cyclin D1 plays a crucial role in regulating the cell cycle's G1/S transition, and its interaction with SUSD2 could be significant in cancer biology.

### 2. Aging and Age-Related Diseases

While specific literature regarding SUSD2 and aging is limited, it is important to note the following:

- Tumor Suppression: As SUSD2 is implicated in the regulation of the cell cycle and cell division, its role as a potential tumor suppressor positions it at the crossroads of age-related oncogenesis, where aging increases the risk of cancer development.
- Inflammation: Dysregulation of cytokines, which may involve SUSD2 indirectly through GPR15LG, is often associated with various age-related diseases, including cardiovascular diseases and neurodegenerative disorders.

### 3. Drugs or Drug Classes

Currently, there are no well-documented drugs or drug classes that specifically target SUSD2. However, potential interactions might belong to:

- **Anticancer therapeutics:** Given SUSD2’s tumor suppressor roles, traditional chemotherapeutics that target cell proliferation and growth could interact indirectly with its function.
- **Cytokine inhibitors:** Since SUSD2 may act as a cytokine receptor, drugs modulating cytokine networks could potentially influence its activity.

### 4. Pathways and Biological Processes

SUSD2 is involved in several important biological processes and pathways, including:

- **Cell Cycle Regulation:** It plays a significant role in the transition from G1 to S phase and is involved in cell division mechanisms.
- **Tumor Suppression Pathways:** SUSD2 may interact with pathways governing tumor suppression, apoptosis, and the regulation of cellular proliferation.
- **Inflammatory Responses:** Given its potential role as a cytokine receptor, SUSD2 might be involved in signaling pathways associated with inflammation.
- **Breast Cancer Pathways:** Specifically implicated in regulatory mechanisms pertinent to breast tumorigenesis.

### Summary

In summary, SUSD2 is a potentially significant gene in regulating cell proliferation and tumor suppression, bearing implications in cancer biology and possibly aging-related processes. Its interaction with various pathways and genes underscores its relevance in these complex biological contexts. Further research may elucidate additional roles and therapeutic avenues concerning SUSD2.