Neoplasia 2: Spread of Malignant tumors Flashcards
(35 cards)
Explain how Malignant tumors invades ECM
- Tumor cell loses cell cohesion and detaches from rest of tissue by loss of Cadherin
- Attachement of tumor cell to laminin of basement membrane & fibronectin of ECM
- Degredation of ECM by Typer 4 collagenase & Cathepsin D
- Migration of tumor cell by pseudopodia using autocrine mobility factors
- Acquirement of negative charges on its surface to repel other cells —> loss of contact (cell to cell) inhibition
Enzymes used by malignant tumors to degrade ECM, & their function
- Type 4 collagenase: lysis of basement membrane
- Cathepsin D: lysis of interstitium
Explain how tumor gains mobility & pseudopodia
by tumor- derived cytokine= Autocrine motility factors
Order of BV from most penetrable to least penetrable by tumor
- Lymphatics
- Capillaries
- Venules
- (rarely) Arterioles
Explain who lymphatics are the most penetrable by tumors
due to lack of basement membrane
Describe fate of tumor emboli
- Most tumors emboli are destroyed by immune system
- Some adhere to platelets, protecting themselves from immune system
- They get impacted into small vessels, then adhere to endothelium, then cross the basement membrane, to reach & settle in a new site (homing)
Define organ tropism
Expression of adhesion molecules on the tumor cell whose ligands are expressed by endothelial & the metastic site, or chemokine receptors on the tumor cell
Examples of organ tropism
- Prostatic carcinoma spreads to bone
- bronchogenic carcinoma spreads to adrenal glands or brain
- Neuroblastoma to liver & bones
Routes of spread of tumor is divided into ____
- Direct (local) spread
- Distal spread= Metastis
define direct/local spread
progressive infiltration, invasion & destruction of surrounding tissue
Which type of tissue delays local spread of tumor
- Bone
- Cartilage
- elastic tissue
- fibrous tissue
Metastis is divded into ___
- Lymphatic spread
- Blood (hematogenous) spread
- Transcoelomic Spread
- Transluminal Spread
Lymphatic spread is more common in what type of Cancer
Carcinoma (than sarcoma)
gross pathology of tumor emboli of Lymph nodes
- Enlarged
- hard
- fixed
- painless
explain how lymphatic spread reaches hematogenous spread
tumor spreads in lymph to reach main lymphatic ducts (thoracic duct) —> Venous circulation—> blood
Definition of Lymphatic permeation
Solid columns inside lymphatics causing obstruction (no drainage) —> Lymphatic edema
which cancer shows lymphatic permeation (lymphatic edema)
Breast cancer
Clinical diagnosis of enlarged LN near primary neoplasm
- Doesn’t mean cancer has infiltrated the node
- may be due to necrotic products of the neoplasm & tumor antigens stimulates immunologic response in the node (Lymphadenitis)/ sinus histocytosis (macrophage accumulation at sinuses)
Define sentient lymph node
First regional lymph node receiving lymph from site of primary tumor
Explain how sentient LN is traced and studied
- Inject blue dye/ radiolabeled tracers near the site of tumor
- remove LN & study (biopsy) using frozen section
Most common organs affected by Hematogenous spread
- Liver
- Brain
- Lung
- Bone
LBLB
Explain how lung metastases come from blood spread
Emboli moves in systemic veins from organ to right side of the heart via Vena Cava —> Pulmonary arteries —> Lung Metastase
how does primary/metastic lung cancer spread to other organs
Emboli spreads through pulmonary veins to left side of the heart —> Aorta —> systemic arterial circulation
Emboli reach portal veins from GIT may cause Metastase in ___
Liver
