Cancer Metastasis Mechanisms and Stages

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Questions and Answers

Which of the following factors can accelerate the development of mutations leading to cancer?

Regular exercise

Eating fruits and vegetables

Tobacco use (correct)

Drinking water

Only a small percentage of circulating tumor cells (CTCs) can form metastatic tumors.

True

What is the role of angiogenesis in the development of metastasis?

Angiogenesis promotes the development of new blood vessels that provide pathways for cancer cells to enter circulation.

To survive in circulation, cancer cells are often coated by ______ to protect against immune detection.

platelets Signup and view all the answers

Match the following components with their functions in cancer metastasis:

Type IV Collagenase = Breaks down the basement membrane Cathepsin B = Degrades extracellular matrix components Platelets = Protects cancer cells in circulation Lymphogenesis = Develops new lymphatic vessels for transport Signup and view all the answers

What must metastatic cancer cells do to invade new tissues?

Enter the lymphatic and blood circulation Signup and view all the answers

Local carcinoma is generally lethal without progression to metastatic cancer.

False Signup and view all the answers

What characteristic do successful metastatic cancer cells exhibit to evade the immune system?

Low immunogenicity Signup and view all the answers

What helps cancer cells navigate endothelial barriers?

Gene activation Signup and view all the answers

Cancer cells must adapt to new tissue environments to establish colonies.

True Signup and view all the answers

What is the Seed-Soil Hypothesis?

It describes how only specific tissues provide a favorable environment for cancer cells to thrive. Signup and view all the answers

Cancer cells can become motile and invasive through the process of __________.

Epithelial-Mesenchymal Transition (EMT) Signup and view all the answers

Match the type of cancer with its preferred metastatic site:

Prostate cancer = Liver Colon cancer = Bone Breast cancer = Bone, lungs Lung cancer = Brain Signup and view all the answers

Which pathways are activated during the Epithelial-Mesenchymal Transition (EMT)?

Hedgehog and Wnt signaling Signup and view all the answers

Cancer cells can revert from a mesenchymal state back to an epithelial state through Metastatic Epithelial Transition (MET).

False Signup and view all the answers

How do cancer cells suppress the immune response?

By actively suppressing it through various mechanisms. Signup and view all the answers

To invade new tissues, cancer cells rely on the degradation of the __________ and ECM.

basement membrane Signup and view all the answers

What drives cancer cells to execute complex steps quickly, such as invasion and metastasis?

Plagiarizing normal biological processes Signup and view all the answers

Study Notes

Cancer Metastasis: Steps and Mechanisms

Human cancers progress through a series of steps forming primary tumors, then potentially metastasizing.
Factors like fast food, processed meat, and tobacco use accelerate mutation development, impacting cancer progression, including lung cancer.
Primary tumors can become metastatic, posing a greater threat than local cancer.

Development of Metastatic Cancer

Circulating Tumor Cells (CTCs) are shed from primary tumors into the bloodstream.
A minuscule fraction (less than 0.01%) of these cells become metastatic.
Metastatic cells must meet specific requirements:

Metastatic Cell Requirements

Leaving the Primary Tumor:
- Proteinases degrade basement membrane and extracellular matrix (ECM), enabling escape.
- Key enzymes involved: Type IV Collagenase and Cathepsin B.
Entering the Circulation:
- Angiogenesis and lymphogenesis establish pathways for cancer cell entry.
- Cancer cells separate, exhibit motility to move towards blood/lymph vessels.
Surviving in the Circulation:
- Platelets coat cancer cells, protecting them from immune response and stress.
- Selectin-mediated binding of platelets creates a protective layer.
Overcoming Host Defenses:
- Low immunogenicity and immune suppression are common.
Extravasation (Exiting Blood Vessels):
- Cancer cells navigate non-porous blood vessels at distant sites.
- Motility, flexibility, and activation of specific genes needed.
- ECM & basement membrane degradation facilitates invasion of new tissues.
Establishing a Metastatic Colony:
- Cancer cells adapt to new tissue environments; establish colonies.
- The Seed-Soil Hypothesis describes the need for compatible tissue environments.

Seed-Soil Hypothesis

A tumor's metastatic potential depends on interactions with tissues promoting growth and survival.
Specific tissues are "best soil" for particular cancers (e.g., prostate cancer to bone).
Cancer cells select the optimal environment for growth, similar to seeds choosing favorable soil.

EMT and MET: Cellular Transformation

Cancer cells employ normal biological processes, such as the epithelial-mesenchymal transition (EMT), for metastasis.
EMT (embryonic process) allows cells to transition from non-motile, structured epithelium to motile, flexible mesenchyme.
In Cancer: Epithelial cancer cells, undergoing EMT, reduce epithelial markers and gain mesenchymal properties.
This enables invasion, entry into circulation, and survival.
Mesenchymal cells are adapted for motility, invasion, and circulation.
Cells re-establish the epithelial structure (MET) at the secondary site, forming new tumors.
Metastatic process largely driven by epigenetic modifications.
Key transcription factors (TFs), activated by pathways like Hedgehog (Hh) and Wnt—critical in embryonic development—are frequently involved in cancers.
Initial mutations in regulatory genes (e.g., APC) can drive cancers into EMT-related pathways.

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Description

This quiz explores the intricate processes involved in cancer metastasis, highlighting the steps from primary tumors to metastatic cells. Learn about the factors that influence cancer progression and the specific requirements that metastatic cells must meet to spread throughout the body. Test your knowledge on this critical aspect of cancer biology.