Flashcards in CH3 - Principles of Neoplasia Deck (169)
Angiogenesis and tumors
(production of new blood vessels) is necessary for tumor survival and growth.
FGF and VEGF
(angiogenic factors) are commonly produced by tumor cells.
Tumor survival and the immune system?
Avoiding immune surveillance is necessary for tumor survival
Immune surveillance and tumor survival?
Mutations often result in production of abnormal proteins, which are expressed on MHC class 1, CD8+ T cells detect and destroy such mutated cells, Tumor cells can evade immune surveillance by downregulating expression of MHC class 1.
How do tumor cells evade immune surveillance?
by downregulating MHC class 1
Immunodeficiency and cancer
(both primary and secondary) increases risk for cancer
Accumulation of mutations eventually result in what?
tumor invasion and spread
Epithelial tumor cells are normally attached to one another by what?
cellular adhesion molecules (e.g., E-cadherin).
Downregulalion of E-cadherin leads to what?
dissociation of attached cells
How do the tumor cells spread locally?
Cells attach to laminin and destroy basement membrane (collagen type IV) via collagenase. Cells attach to fibronectin in the extracellular matrix and spread locally
Metastasis of tumor cells.
Entrance into vascular or lymphatic spaces allows for metastasis (distant spread)
What are the routes of metastasis?
Lymphatic, hematogenous, seeding of body cavities
Lymphatic spread is characteristic of what?
Where does the initial lymphatic spread occur?
In the regional draining lymph nodes
Hematogenous spread is characteristic of what?
sarcomas and some carcinomas
What are some examples of hematogenous spread?
renal cell carcinoma, hepatocellular carcinoma, follicular carcimoma of the thyroid, choriocarcinoma
Seeding of body cavities is characteristic of?
ovarian carcinoma, often involves the peritoneum 'omental caking'
What is omental caking?
where the peritoneum is often involved in ovarian carcinoma
Describe benign tumors.
tend to be slow growing, well circumscribed, distinct, and mobile
Malignant tumors are usually
rapid growing, poorly circumscribed, infiltrative, and fixed to surrounding tissues and local structures.
What is generally required before a tumor can be classified as benign or malignant with certainty?
Biopsy or excision
Why is biopsy necessary?
Some benign tumors can grow in a malignant-like fashion, and some malignant tumors can grow in a benign-like fashion.
Benign tumors are usually
What are some characteristics of benign tumors?
1. Organized growth 2. Uniform nuclei 3. Low nuclear to cytoplasmic ratio 4. Minimal mitotic activity 5. Lack of invasion (of basement membrane or local tissue) 6. No metastatic potential
Malignant tumors are classically
poorly differentiated (anaplastic)
Characteristics of malignant tumors include
1. Disorganized growth (loss of polarity) 2. Nuclear pleomorphism and hyperchromasia 3. High nuclear to cytoplasmic ratio 4. High mitotic activity with atypical mitosis 5. Invasion (through basement membrane or into local tissue)
What is the hallmark of malignancy?
Metastatic potential - benign tumors never metastasize
What is the target cell type for the immunohistochemical stain of Keratin?
What is the target cell type for the immunohistochemical stain of Vimentin