Understanding Oncogenes and Their Role in Cancer

Oncogenes are important parts of our DNA that can cause normal cells to turn into cancer cells. When these genes change or are too active, they can lead to the growth of tumors. By studying oncogenes, scientists gain insight into how cancer develops, making them a key area of focus in cancer research.

Types of Oncogenes

1. Proto-oncogenes: These are normal genes. However, if they get changed (mutated), they can become oncogenes. Here are some examples:

   • RAS gene family: About 30% of human cancers have RAS mutations. This is especially true for cancers like pancreatic, colorectal, and lung cancer.
   • MYC: This gene helps control the cell cycle. It is often found in high amounts in cancers like Burkitt lymphoma and breast cancer.
   • HER2/neu: About 20-30% of breast cancers have extra copies of this gene, which can lead to fast tumor growth.

2. Mutated Oncogenes: When proto-oncogenes change, they can cause cells to grow out of control. Some types of changes include:

   • Point mutations (like those found in RAS)
   • Gene amplifications (like those with HER2/neu)
   • Chromosomal shifts (like BCR-ABL in chronic myeloid leukemia)

How Oncogenes Cause Cancer

Oncogenes can lead to cancer in several ways:

• Increased cell growth: Oncogenes can make cells grow too quickly by bypassing normal controls.
• Avoiding programmed cell death: Oncogenes can stop cells from dying when they should, letting unhealthy cells live and multiply.
• Changing how cells communicate: Mutated oncogenes can disrupt normal signals, helping tumors spread and invade other tissues.

Facts and Figures

• Cancers Linked to Oncogenes: Many common cancers include oncogenes:
  • Over 80% of pancreatic cancers have K-RAS mutations.
  • About 25% of breast cancers have too much HER2.
• Mutation Rates:
  • In solid tumors, oncogene mutations can be found about 15-20% of the time. For example, almost 40% of colorectal cancer cases have changes in the APC gene, which usually prevents tumors, while 50% show oncogene mutations.

Treatment Options

Understanding oncogenes helps in creating specific treatments:

• Monoclonal Antibodies and Tyrosine Kinase Inhibitors: These targeted therapies include:
  • Trastuzumab for breast cancer that is HER2-positive.
  • Imatinib for chronic myeloid leukemia with the BCR-ABL mutation.
• Success Rates: Treatments aimed at oncogenes have improved patient outcomes:
  • Trastuzumab can lower the risk of dying by 52% compared to treatments that do not use it.

In conclusion, oncogenes are crucial in how cancer develops by changing the way cells function and grow. Ongoing research into these genes helps create better ways to diagnose and treat cancer.