Neoplasia II: Invasion and Metastasis

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Questions and Answers

What characterizes invasion in tumor biology?

Tumor cells remain in a localized mass.

Tumor cells migrate in a cohesive manner.

Tumor cells spread exclusively through lymphatic channels.

Tumor cells penetrate blood vessels. (correct)

Which type of tumor is associated with the ability to metastasize?

Neurofibromas

Benign tumors

Malignant tumors (correct)

Pre-cancerous lesions

What is the primary distinction between benign and malignant tumors regarding growth?

Benign tumors lack the ability to infiltrate. (correct)

Malignant tumors do not have localized growth.

Malignant tumors remain cohesive masses.

Benign tumors invade surrounding tissues.

What is a key component of the extracellular matrix (ECM) that tumor cells degrade to facilitate invasion?

Collagen Signup and view all the answers

What is the first step in the metastatic cascade?

Loosening cell-cell interactions Signup and view all the answers

Which characteristic is true of the metastatic process?

It leads to the formation of secondary tumors. Signup and view all the answers

What is the primary role of cadherins in normal cells?

Mediate cell-cell interactions Signup and view all the answers

What changes occur in cancer cells that affect cell adhesion?

Alterations in adhesion molecules Signup and view all the answers

What is a function of integrins in cells?

Adhesion to the basement membrane Signup and view all the answers

What does the reduction of integrins in cancer cells lead to?

Altered cell movement Signup and view all the answers

Which family of proteins is primarily involved in intercellular adhesion?

Cadherins Signup and view all the answers

What role do proteases play in tumor cell behavior?

They degrade basement membranes Signup and view all the answers

What is the relationship between catenins and cadherins?

Catenins connect cadherins to the cytoskeleton Signup and view all the answers

What triggers the synthesis of more enzymes by fibroblasts in the tumor environment?

Factors synthesized by malignant cells Signup and view all the answers

What is the significance of lymph node involvement in cancer?

It assists in assessing disease stage and treatment strategies. Signup and view all the answers

Which of the following sites is most commonly involved in hematogenous metastasis?

Liver Signup and view all the answers

What type of cancer is most likely to cause brain metastasis?

Bronchial carcinoma Signup and view all the answers

Which condition causes an obstruction in hollow viscera due to malignant tumors?

Partial or complete obstruction Signup and view all the answers

Which process describes the spread of tumor cells to body cavities?

Seeding of body cavities Signup and view all the answers

What effect do benign tumors generally have on surrounding tissue?

They cause pressure atrophy and obstruction. Signup and view all the answers

What is one of the primary roles of matrix metalloproteinases (MMPs) in tumor invasion?

Dissolving components of the basement membrane Signup and view all the answers

Which MMP is known as a gelatinase that cleaves type IV collagen?

MMP9 Signup and view all the answers

How do receptors, like integrins, contribute to the state of normal epithelial cells?

They help maintain a resting, differentiated state. Signup and view all the answers

What is one reason why not all malignant cells metastasize?

Incorrect environmental conditions at the target site Signup and view all the answers

What type of spread is most common for the initial dissemination of carcinomas?

Lymphatic spread Signup and view all the answers

What is a characteristic feature of tumor cells in relation to cell death?

They are resistant to apoptosis induced by loss of adhesion. Signup and view all the answers

Which type of cell migration involves numerous cells moving together?

Collective cell migration Signup and view all the answers

What is required for the migration of tumor cells through degraded basement membranes?

Cell-derived motility factors Signup and view all the answers

Which pathway is NOT associated with metastasis?

Circumstantial spread Signup and view all the answers

What effect do cleavage products of matrix proteins have on tumor cells?

They stimulate migration through novel binding sites Signup and view all the answers

Study Notes

Invasion and Metastasis

Invasion refers to the ability of tumor cells to break through the basement membrane and invade surrounding tissues, distinguishing malignant tumors from benign ones, which remain localized.
Metastasis indicates tumor spread to distant sites, signifying malignancy and requires tumor cells to undergo a series of steps known as the metastatic cascade.
The metastatic cascade includes: loosening cell-cell interactions, degrading extracellular matrix (ECM), attaching to new ECM components, and migrating to secondary sites.

Tumor Cell Invasion Mechanisms

Tumor cells detach from each other due to changes in intercellular adhesion molecules, particularly cadherins which typically bind normal cells together.
Integrins play a crucial role in cell adhesion and migration; reduced expression allows tumor cells to move more freely.
Tumor cells degrade the basement membrane and interstitial connective tissue through protease enzymes like Matrix metalloproteinases (MMPs), which facilitate invasion and release growth factors from the ECM.

Pathways of Metastasis

Metastasis occurs primarily via three pathways:
- Lymphatic spread, common for carcinomas.
- Hematogenous spread, typical for sarcomas.
- Direct seeding into body cavities (e.g., Krukenberg tumors).
Lymphatic spread leads to cancer cells in draining lymph nodes, critical for disease staging and therapy selection.
Hematogenous spread mainly targets the liver, lungs, bone marrow, and can occur in various malignancies including carcinomas and sarcomas.

Local Effects of Tumors

Benign tumors generally cause local effects such as compression, atrophy, altered function, and obstruction of hollow viscera.
Malignant tumors destroy surrounding tissue, invade nerves and blood vessels, and cause ulceration.

Systemic Effects of Neoplasms

Cancer cachexia features progressive weight loss, weakness, and increased metabolic rate despite poor food intake.
Hematological effects include anemia from ulceration or infiltration of bone marrow, alongside leukopenia and thrombocytopenia due to infiltration or treatment.
Endocrine disturbances can arise from excessive hormone secretion or ectopic hormone production from neoplasms, leading to syndromes like Cushing’s disease.

Neuromuscular and Skin Effects

Neuromuscular symptoms include balance problems, sensory/motor neuropathies, and myopathy.
Skin manifestations can include increased pigmentation, pruritus, and conditions such as dermatomyositis.

Paraneoplastic Syndromes

These syndromes involve symptom complexes that are not easily explained by the tumor's local or systemic effects, potentially being the first indicator of an occult neoplasm.
Types of paraneoplastic syndromes include:
- Endocrinopathies, especially Cushing's syndrome resulting from ectopic hormone production.
- Hypercalcemia due to osteolysis from cancer or humoral substances from neoplasms.
- Skin changes, such as acanthosis nigricans, noted by gray-black patches in skin folds.

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Description

This quiz covers the crucial concepts of invasion and metastasis as related to neoplasia. Learn about how malignant cells differ from benign tumors and their ability to infiltrate and spread through tissues. Enhance your understanding of tumor behavior and characteristics.