Cancer includes many diseases in which cells grow or behave abnormally. This lesson explains how changes to cell-cycle regulation can allow cells to keep dividing, and how tumor-suppressor genes and oncogenes influence this process.
The cell cycle is a sequence of stages through which a cell grows, copies its DNA, and divides. Before a cell moves from one phase to another, it must pass checkpoints. These control points help ensure that the preceding step was completed properly and that the cell has not acquired damage or mutations that make continued division unsafe.
All flashcards
What is a cell-cycle checkpoint?
A control point that checks whether a cell has properly completed a stage and whether it is appropriate to proceed.
How may cyclin B contribute to cancer?
Cyclin B helps regulate cell-cycle progression. Abnormal regulation, such as altered phosphorylation, can disrupt this control and let cells progress despite mutations.
What does a tumor-suppressor gene do?
It normally helps restrain excessive or inappropriate cell growth. Mutation or silencing can remove some of this protective control.
What is the role of p53?
p53 is a tumor-suppressor protein that acts as a transcription factor, binding promoter regions and influencing transcription of target genes.
How do proto-oncogenes differ from oncogenes?
Proto-oncogenes are normal positive regulators of growth. When abnormally activated or overexpressed, they can become oncogenes that promote cancerous growth.
Quiz questions
How can aberrant myc activity contribute to Burkitt lymphoma?Answer: Excess myc can drive B cells toward cancerous, uncontrolled growth.
How can a mutation in a promoter or enhancer increase gene expression?Answer: It can make the regulatory DNA site bind a transcription factor more readily.
In some breast cancers, what sequence links EGFR signaling to altered gene expression?Answer: EGFR activation, protein kinase activity, transcription-factor activity, then altered target-gene expression.
What is a defining aim of targeted therapy for cancer?Answer: Acting on a particular molecular feature of diseased cells.
Which task is commonly part of a clinical trial coordinator's role?Answer: Coordinating participant appointments and maintaining trial records.
Based on Biology 2e by Mary Ann Clark, Matthew Douglas, Jung Choi (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.