In this chapter, we focused on cancer as a genetic disease, with an emphasis on the relationship between cancer, the cell cycle, and DNA damage, as well as on the multiple steps that lead to cancer. At the same time, we found many opportunities to consider the methods and reasoning by which much of this information was acquired. From the explanations given in the chapter,

How do we know that cancer cells contain defects in DNA repair?

Key Concepts

DNA Repair Mechanisms

DNA repair mechanisms are cellular processes that identify and correct damage to the DNA molecules that encode an organism's genome. These mechanisms are crucial for maintaining genomic stability and preventing mutations that can lead to diseases, including cancer. Defects in these repair systems can result in the accumulation of genetic errors, which is a hallmark of cancer cells.

Cell Cycle Regulation

The cell cycle is a series of phases that a cell goes through to grow and divide. Proper regulation of the cell cycle is essential for normal cell function and prevents uncontrolled cell proliferation. Cancer cells often exhibit dysregulation of the cell cycle, which can be linked to defects in DNA repair, allowing them to bypass checkpoints that would normally halt division in response to DNA damage.

Genetic Mutations and Cancer

Genetic mutations are changes in the DNA sequence that can lead to altered protein function and contribute to the development of cancer. Mutations can arise from various sources, including environmental factors and errors during DNA replication. In cancer cells, the presence of mutations often correlates with defects in DNA repair pathways, leading to further genomic instability and tumor progression.