What is the substance that produces cancer?

Cancer is caused by mutations in the DNA of cells, which can be caused by a variety of factors, including:

1) Carcinogens: Carcinogens are substances or agents that can cause cancer by damaging DNA. They can be found in tobacco smoke, certain chemicals, radiation, and some viruses.

2) Oncogenes: Oncogenes are genes that have mutations that cause them to produce proteins that promote cancer cell growth and division. These mutations can be inherited or acquired during a person's lifetime.

3) Tumor suppressor genes: Tumor suppressor genes are genes that help control cell growth and division. Mutations in these genes can allow cells to grow and divide uncontrollably, leading to cancer.

In most cases, cancer is caused by a combination of genetic factors and environmental factors, such as exposure to carcinogens.