The genes which on activation produce malignant neoplasm are

Options

A. Pleiotropic genes
B. Multiple genes
C. Oncogenes
D. Neonatal genes

Answer

**Step-by-Step Solution:**

1. **Understanding Neoplasm**:
- A neoplasm is defined as an abnormal growth of cells, which can lead to tumors. When these tumors are cancerous, they are referred to as malignant neoplasms.

2. **Characteristics of Malignant Neoplasms**:
- Malignant neoplasms invade nearby healthy tissues and have the potential to spread to other parts of the body, which distinguishes them from benign tumors.

3. **Identifying Relevant Genes**:
- The question asks for genes that, when activated, can lead to malignant neoplasms.

4. **Defining Oncogenes**:
- Oncogenes are specific genes that, when activated (often due to mutations or external factors), can promote the development of cancer. They are typically inactive in their normal state but can lead to uncontrolled cell growth when activated.

5. **Evaluating Other Options**:
- The other options provided (leotropic genes, multiple genes, neonatal genes) do not specifically relate to the development of malignant neoplasms:
- **Leotropic genes**: These are not commonly recognized in the context of cancer.
- **Multiple genes**: This term generally refers to polygenic traits and does not specifically indicate cancer.
- **Neonatal genes**: These refer to genes present in newborns and are not related to the activation of malignant neoplasms.

6. **Conclusion**:
- Based on the definitions and characteristics discussed, the correct answer to the question is **oncogenes**.

**Final Answer**: The genes which on activation produce malignant neoplasm are **oncogenes**.

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