Neoplasia II: Tumor Invasion and Metastasis

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Questions and Answers

What local effect can benign neoplasms have on surrounding tissues?

Compression causing pressure atrophy (correct)

Intravenous infiltration

Complete tissue destruction

Metastatic spread

Which of the following is a common systemic effect of neoplasms?

Anaemia (correct)

Leukocytosis

Local inflammation

Hyperplasia

Which neoplasm can cause ectopic hormone secretion?

Benign meningioma

Small cell carcinoma of bronchus (correct)

Hepatoma

Leiomyoma

Which effect is specifically associated with malignant neoplasms?

Infiltration around nerves and blood vessels Signup and view all the answers

What is a potential consequence of raised intracranial pressure (ICP) due to neoplasms?

Perforation of tissues Signup and view all the answers

Which symptom is indicative of cachexia associated with neoplasms?

Muscle atrophy Signup and view all the answers

Neuromuscular issues related to neoplasms may include which of the following?

Sensorimotor neuropathies Signup and view all the answers

What can result from the infiltration of the bone marrow due to neoplasms?

Low white cell count Signup and view all the answers

What primarily causes the need for angiogenesis in a tumor?

Hypoxia due to insufficient nutrients Signup and view all the answers

Which of the following is NOT a route of metastasis?

Nervous system Signup and view all the answers

Which type of carcinoma is commonly known to metastasize to the liver?

Bronchial carcinoma Signup and view all the answers

What is a possible effect of metastasis to bone?

Pathological fractures due to bone destruction Signup and view all the answers

Which of the following factors does NOT determine the effects of tumors?

Site of kidney function Signup and view all the answers

Angiogenesis is primarily regulated by which of the following factors?

Pro-angiogenesis factors like VEGF Signup and view all the answers

What does the term 'primary tumor' refer to?

The original site of malignant neoplasm Signup and view all the answers

What can result from vascular spread to the brain?

Space occupying lesion causing neurological symptoms Signup and view all the answers

What role do Matrix Metalloproteinases (MMPs) play in tumor cell behavior?

They aid in the breakdown of the basement membrane. Signup and view all the answers

Which of the following factors can potentiate the movement of cancer cells through the stroma?

Cell derived motility factors. Signup and view all the answers

Which of the following describes the ECM in relation to cancer invasion?

It can either promote or inhibit cell invasion. Signup and view all the answers

What is the primary feature of metastasis in cancer cells?

Invasion into lymphatics and blood vessels. Signup and view all the answers

Why do not all cancer cells that circulate successfully establish metastases?

They may encounter unfavorable conditions in target tissues. Signup and view all the answers

What determines the organ distribution of metastases in relation to the primary tumor?

Vascular and lymphatic drainage pathways. Signup and view all the answers

Which chemokine receptor is associated with human breast cancer cells for metastasis?

CXCR4 Signup and view all the answers

What is the primary characteristic of malignant cells in terms of adhesion?

Malignant cells do not adhere as strongly as normal cells. Signup and view all the answers

What happens once tumor cells reach their target organ?

They must colonize and adapt to the new environment. Signup and view all the answers

What type of cancer is associated with the loss of E cadherin?

Lobular carcinoma of the breast Signup and view all the answers

Which of the following is a characteristic feature of metastasis?

Spread of malignant tumors to distant sites Signup and view all the answers

What role do integrins play in cancer cell invasion?

They modify the contact between cells and the stroma. Signup and view all the answers

What is one of the mechanisms facilitating invasion by malignant cells?

Altered synthesis of enzymes degrading extracellular matrix Signup and view all the answers

Which factors contribute to the motility of malignant cells?

Presence of motility factors Signup and view all the answers

How do malignant cells interact with the surrounding stroma?

They alter their interactions, leading to looser attachment. Signup and view all the answers

What is the definition of invasion in the context of tumors?

Cells break through the basement membrane and invade surrounding tissues. Signup and view all the answers

Study Notes

Neoplasia II: Invasion, Metastasis, and Effects of Tumors

Invasion: Ability of cells to penetrate the basement membrane and spread through the stroma (extracellular matrix). Two key mechanisms:
- Spreading into surrounding tissue (Invasive Carcinoma).
- Entering lymphatic/vascular channels, characteristic of malignant cells.

Metastasis

The spread of a malignant tumor to a distant (non-adjacent) site.
A metastasis is also known as a secondary tumor, originating from the primary tumor.

Mechanisms of Cell Invasion and Spread

Malignant cells have altered adhesion compared to normal cells, sticking less.
Changes in enzyme production break down basement membranes and stroma.
Motility factors help cells move.
Malignant cells change their interaction with surrounding stroma.

Altered Cell Adhesion

Cadherins: Calcium-dependent glycoproteins at cell membranes. Interact homotypically to bind cells together. Linked to the actin cytoskeleton via catenins. Reduced expression in cancer cells allows cells to separate. (Examples: esophagus, colon, breast, prostate cancers)
Integrins: Cell surface glycoproteins with α and β subunits. Many biological functions (e.g., leukocyte and platelet adhesion). Receptors for different components of the basement membrane (e.g., fibronectin, collagen) . Reduced expression alters cell-stroma contact, facilitating cell movement.

Altered Enzyme Synthesis and Interaction

Different enzymes modify the stroma, allowing cells to breach basement membranes and spread.
Matrix metalloproteinases (MMPs) are zinc-dependent enzymes that degrade the extracellular matrix (ECM).
- MMP2 and MMP9 break down collagen IV.
- MMP1 breaks down collagen I.
These changes in attachment alter tumor cell interactions with ECM proteins.

Cell Motility

Disrupted basement membrane and stroma allow cells to move.
Potentiated and directed by factors:
- Cell-derived motility factors (autocrine motility factors).
- Cleavage products of matrix proteins (e.g., laminin).
- Other ligands, such as Wnt5a (in melanoma).
- Increased expression of receptors for motility factors (e.g., Met oncogene, HGF receptor).

Metastasis Routes

Lymphatics: Spread to local and distant lymph nodes; a frequent route for carcinomas; lungs can be involved.
Blood vessels: Spread via capillaries and veins to other organs. Common sites include lungs, liver, bone, and brain.
Coelemic spaces: Another pathway.

Importance of ECM

The extracellular matrix (ECM, or stroma) isn't passive; it can promote or inhibit invasion.
Malignant cells manipulate the ECM for facilitated passage (e.g., using growth, angiogenic, and chemotactic factors)

Why Don't All Malignant Cells Metastasize?

Cells may invade and circulate but the environment might not be suitable.
Incorrect receptor expression or metabolic factors may hinder their growth.
Failure of angiogenesis can be another reason.

Angiogenesis

Tumor growth halts beyond 1-2mm³ due to nutrient/oxygen depletion, altering the microenvironment.
Upregulation of pro-angiogenesis factors (e.g., angiopoietin, VEGF) occurs, leading to new blood vessel growth.
This growth enables continued tumor growth, providing access to the bloodstream.
Thalidomide is a therapeutic target in renal cancers.

Definitions: Primary and Secondary Tumors

Primary: The site where the malignant neoplasm first arises (e.g., breast, stomach).
Secondary: A metastasis; a cancerous tumor that has spread to another organ (e.g., Breast carcinoma that spread to another organ).

Effects of Tumors

Tumor effects depend on factors:
- Tumor site.
- Extent of local spread.
- Metastatic site.
- Extent of metastatic spread.
- Functional effects (e.g., pituitary).

Local Effects of Benign Neoplasms

Compression (pressure atrophy).
Altered function.
Obstruction (hollow viscus).
Erosion/ulceration.
Space-occupying lesion.

Local Effects of Malignant Neoplasms

Tissue destruction.
Obstruction or constriction.
Ulceration.
Invasion and infiltration around nerves, blood vessels, and lymphatics.
Space-occupying lesion.

Systemic Effects: Haematological

Anemia (due to ulceration, bone marrow infiltration, or haemolysis).
Low white blood cell and platelet counts (bone marrow infiltration).
Thrombosis (e.g., pancreatic carcinoma).

Systemic Effects: Endocrine

Excessive hormone secretion (benign and malignant endocrine glands).
Ectopic hormone secretion (e.g., ACTH by small cell lung cancer).

Systemic Effects: Skin and Others

Pigmentation changes.
Herpes zoster.
Jaundice.
Dermatomyositis.
Hodgkin's disease.
Neuromuscular issues (e.g., balance problems, neuropathies, myopathy).
Cachexia (weight loss).
Malaise (general discomfort).
Fever (pyrexia).

Why Neoplasms Kill People

Local effects (raised intracranial pressure, perforation, hemorrhage).
Replacement of essential body organs (bone marrow, lung, liver).

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Description

Explore the complex mechanisms behind tumor invasion and metastasis in this quiz on neoplasia. Learn about how malignant cells spread through tissues and invade distant sites, including the role of altered adhesion and enzyme production. Test your knowledge on the various strategies employed by tumors to establish secondary sites.