Cancer Biology Quiz: Tumor Invasion and Metastasis

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Questions and Answers

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

Decreased adherence to the same extent as normal cells (correct)

Increased adhesion to surrounding tissues

Ability to grow in a confined area

Being restricted to vascular channels

What is a common characteristic of a metastasis?

It is referred to as a secondary tumor (correct)

It forms at the site of the primary tumor

It typically remains in the same tissue type

It leads to benign growths

Which of the following factors contributes to the motility of malignant cells?

Motility factors produced by malignant cells (correct)

Cadherins binding tightly

Decreased interactions with other cells

Increased synthesis of structural proteins

What role do integrins play in tumor cell invasion?

They modify contact between the cell and stroma (B) Signup and view all the answers

Which statement about cadherins is correct?

They help bind tumor cells together (A) Signup and view all the answers

What process facilitates the breakdown of the basement membrane by malignant cells?

Altered enzyme synthesis (C) Signup and view all the answers

Why do neoplasms have the potential to be deadly?

They can metastasize and invade vital organs (D) Signup and view all the answers

What is the primary route through which malignant tumors can spread?

Through both lymphatic and vascular channels (A) Signup and view all the answers

What initiates the growth of new blood vessels in a tumor environment?

Pro-angiogenesis factors (D) Signup and view all the answers

Which of the following is a common site for vascular spread in malignant neoplasms?

Liver (C) Signup and view all the answers

What is a potential local effect of benign neoplasms?

Compression causing pressure atrophy (D) Signup and view all the answers

Which route of metastasis commonly involves local and distant lymph nodes?

Lymphatics (D) Signup and view all the answers

Which of the following describes a systemic effect of neoplasms?

Persistent fever and malaise (B) Signup and view all the answers

What is the primary site of a tumor called?

Primary site (A) Signup and view all the answers

What term describes the spread of cancer through capillaries and veins to various organs?

Vascular spread (A) Signup and view all the answers

What is a common hematological effect associated with neoplasms?

Decreased production of red blood cells (D) Signup and view all the answers

Which of the following carcinomas is known for commonly metastasizing to the bone?

Bronchial carcinoma (B) Signup and view all the answers

In what manner do malignant neoplasms primarily differ from benign ones?

They tend to infiltrate into surrounding tissues. (D) Signup and view all the answers

What is the main characteristic of a secondary tumor?

It is derived from metastasis. (A) Signup and view all the answers

What hormonal secretion can occur due to small cell carcinoma of the bronchus?

Adrenocorticotropic hormone (ACTH) (B) Signup and view all the answers

Which factor does NOT affect the overall effects of tumors?

Size of the patient (D) Signup and view all the answers

Which of the following is a possible mechanism for cachexia caused by neoplasms?

Unexplained metabolic changes (C) Signup and view all the answers

Which of the following best describes a local effect of malignant neoplasms?

Raises intracranial pressure (C) Signup and view all the answers

What symptom is associated with the systemic effect of dermatological issues due to neoplasms?

Itching and jaundice (B) Signup and view all the answers

What role do matrix metalloproteinases (MMPs) play in tumor cell invasion?

They break down the basement membrane and allow cell movement. (D) Signup and view all the answers

Which of the following factors is NOT associated with promoting cell motility in tumors?

Inhibition of adhesion molecules (A) Signup and view all the answers

How does the extracellular matrix (ECM) contribute to tumor invasion?

It can either promote or inhibit tumor cell invasion. (C) Signup and view all the answers

What is a key characteristic of metastasis in malignant cells?

They invade lymphatics, blood vessels, and grow at distant sites. (A) Signup and view all the answers

What mechanisms may explain the organ distribution of metastases?

Expression of adhesion molecules and chemokine receptors by tumor cells. (D) Signup and view all the answers

Why may some tumor cells fail to establish metastases after circling in the bloodstream?

They may not find a compatible environment for growth. (B) Signup and view all the answers

Which chemokine receptors are commonly expressed by human breast cancer cells?

CXCR4 and CCR7 (B) Signup and view all the answers

What is the primary reason that skeletal muscles rarely host metastases?

The tissue does not provide suitable conditions for tumor growth. (D) Signup and view all the answers

Study Notes

Neoplasia II: Invasion, Metastasis, and Effects of Tumors

Objectives include defining invasion and metastasis, describing mechanisms facilitating these processes, outlining metastasis routes and common sites, describing local effects of benign and malignant neoplasms, explaining systemic effects of neoplasms, and explaining why neoplasms cause death.

What is Invasion?

Cells break through the basement membrane and spread through the stroma (extracellular matrix).
Types of invasion:
- Invasive carcinoma (into surrounding tissue)
- Invasion into lymphatic/vascular channels (characteristic of malignant cells).

What is Metastasis?

Spread of a malignant tumour to a distant (non-adjacent) site.
A metastasis is often called a secondary tumour, originating from a primary tumour.

How do Cells Invade and Spread?

Complex mechanisms involving multiple factors:
- Adhesion: Malignant cells exhibit reduced adhesion compared to normal cells.
- Enzyme Synthesis: Enzymes are altered to break down basement membrane and stroma.
- Motility factors: Factors that aid cellular motility are produced.
- Interaction with stroma: Malignant cells modify their interaction with surrounding stroma.

Altered Cell Adhesion

Cadherins: Calcium-dependent glycoproteins at cell membranes, mediating homotypic cell-cell interactions.
Linked to actin cytoskeleton via catenins.
Reduced expression and altered interactions in cancer cells, allowing cells to separate.
Integrins: Surface glycoproteins composed of alpha and beta subunits. They bind extracellular matrix components and cytoskeleton.
Reduced expression of integrins modifies contact between cells and stroma, enabling cell movement.

Altered Enzyme Synthesis and Interaction

Matrix metalloproteinases (MMPs): Zinc-dependent enzymes degrading basement membrane and interstitial connective tissue.
Example MMPs: MMP2 and MMP9 (collagen IV), MMP1 (collagen I).
Impact on ECM proteins: Changes in attachment of tumor cells to extracellular matrix (ECM) proteins.

Motility

Cells are propelled through degraded basement membrane and lysed stroma.
Potentiated and directed by factors:
- Cell-derived motility factors (autocrine motility factors).
- Cleavage products of matrix proteins (e.g., laminin).
- Ligands like Wnt5a (e.g., 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 common route for carcinomas, potentially impacting lung lymphatics.
Blood vessels: Spread through capillaries and veins to various organs (e.g., lung, liver, bone, brain).
- Specific examples of tumors that metastasize to lung: Sarcomas (e.g., osteosarcoma), carcinomas (e.g., breast, stomach, large intestine).
- Specific examples of tumors that metastasize to liver: Carcinomas of large intestine (through portal vein), bronchial carcinoma, breast carcinoma.
- Specific examples of tumors that metastasize to bone: Bronchial carcinoma, breast carcinoma, thyroid carcinoma, renal carcinoma, and prostate.
- Specific examples of tumors that metastasize to brain: Bronchial carcinoma, breast carcinoma, testicular carcinoma, and malignant melanoma.
Coelemic spaces

Why Don't All Malignant Cells Metastasize?

Insufficient cell invasion and circulation.
Inappropriate environment at distant sites for cell growth.
Incorrect receptors.
Metabolic factors.
Failure of angiogenesis.

Angiogenesis

Tumour growth halted after reaching 1-2mm³ due to nutrient/oxygen deficiency.
Hypoxic conditions lead to upregulation of pro-angiogenesis factors (e.g., angiopoietin, VEGF).
This stimulates the formation of new blood vessels, enabling continued tumour growth and access to the bloodstream.
Thalidomide is a therapeutic target for angiogenesis in renal cancer

Tumour Effects - Site and Spread

Primary tumor:
- Site where malignant neoplasm originates (e.g., breast, stomach).
Secondary tumor/metastasis:
- Tumor that has spread to another organ (e.g., breast carcinoma spreading to another organ).
- Site of extravasation (exit from blood/lymphatic vessel) and organotropism (preferential organ localisation) are often predicted by primary tumor features (lymph node drainage/vascular supply)

Effects of Tumors

Local effects depend on tumour site, extent of local spread, site of metastasis, and extent of metastatic spread, as well as functional effects.
Small tumours can cause severe consequences in specific locations.
Effects of benign neoplasms include compression, pressure atrophy, altered function (e.g., pituitary), obstruction (hollow viscus), ulceration, and bleeding

Local Effects of Benign Neoplasms

Compression and pressure atrophy.
Altered function (e.g., pituitary).
Obstruction in hollow organs.
Ulceration and bleeding of surface mucosa.
Space-occupying lesion (e.g., in the brain).

Local Effects of Malignant Neoplasms

Tissue destruction.
Obstruction and constriction in hollow organs.
Ulceration.
Infiltration of nerves, blood vessels, and lymphatics.
Space-occupying lesion (e.g., in the brain).

Systemic Effects of Neoplasms

Haematological (e.g., anaemia, low white blood cells, low platelets, thrombosis).
Endocrine (e.g., excessive hormone secretion, ectopic hormone secretion).
Skin pigmentation, herpes zoster, pruritus, jaundic, dermatomyositis
Neuromuscular (e.g., balance problems, neuropathies, myopathy).
Cachexia (weight loss, muscle atrophy, loss of appetite).
Malaise (general discomfort).
Pyrexia (fever).

Why Do Neoplasms Kill People?

Local effects (e.g., raised intracranial pressure, perforation, hemorrhage).
Replacement of key organs (e.g., bone marrow, lung tissue, liver parenchyma).

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Description

Test your knowledge on the characteristics of malignant cells and their invasive behavior. Explore concepts such as metastasis, integrins, and the systemic effects of neoplasms. This quiz covers critical aspects of cancer biology relevant to tumor invasiveness and spread.