Wk 5 Tumor Pathology Flashcards
What 3 processes are involved in hypertrophy?
- gene activation
- protein synthesis
- production of organelles
What occurs w/ hyperplasia?
Cell production from stem cells
Can permanent tissues undergo hypertrophy and hyperplasia?
Only hypertrophy b/c they cannot make new cells
What are permanent tissues in the human body?
- cardiac myocytes
- skeletal muscle
- nerve
*cannot make new cells so cannot undergo hyperplasia
What is an exception to hyperplasia being pathlogic?
Benign prostatic hyperplasia
-it is pathologic, but no increased risk of cancer
What is the role of atrophy?
Decrease in stress leads to decrease in organ size via decreased size and number of cells
How does a decrease in cell number occur?
apoptosis
What are two pathways to decrease cell size?
- ubiquitin-proteosome degradation of the cytoskeleton
- autophagy of cellular components
3 growth adaptations
- growth via hypertrophy and hyperplasia
- atrophy
- metaplasia
What causes metaplasia?
change in stress on organ -> change in cell type (metaplastic cells can handle new stress better)
-most often involves surface epithelium (squamous k or non, columnar, transitional/urothelium)
What is the mechanism of metaplasia?
reprogramming of stem cells
-reversible w/ removal of the driving stressor
ex. tx of GERD
What can occur w/ metaplasia?
Give an example and exception
Can progress to dysplasia and cancer
ex. Barrett esophagus
exception = apocrine metaplasia - a change seen in fibrocystic changes of the breast
What deficiency can result in metaplasia?
Vitamin A deficiency ->:
1. can go blind
2. -t(15;17) APL involves vitamin A receptor (RAR), causing cells to stay trapped in blast state, accum, -> leukemia
-tx = ATRA (vit A derivative) - binds to mutated receptor and allows cells to mature to neutrophils
3. metaplasia -> thickening of conjunctiva called keratomalacia
-vit A nec to maintain conjunctiva of eye (highly specialized squamous epithelium)
What process can mesenchymal tissues undergo?
metaplasia
bone, BV, fat, cartilage (CTs)
ex. myositis ossificans = inflam of skeletal muscle (usually due to trauma) which then converts to bone. Would be located close to a bone but not touching it b/c in skeletal muscle (diff from osteosarcoma)
Dysplasia
=disordered cellular growth
-refers to proliferation of precancerous cells (ex CIN=cervical intraepithelial neoplasia)
-arises from longstanding pathologic hyperplasia or metaplasia
-can see mitosis high up from basement membrane
Dysplasia
=disordered cellular growth
-refers to proliferation of precancerous cells (ex CIN=cervical intraepithelial neoplasia)
-arises from longstanding pathologic hyperplasia or metaplasia
Mechanism of dysplasia
Stress on cells
-reversible by alleviating stressor
-if stress persists, will progress to carcinoma (irreversible)
What is aplasia?
failure of cell production during embryogenesis
ex. unilateral renal agenesis
Hypoplasia
=decrease in cell production during emobryogenesis
-> small organ
ex. streak ovary in Turner syndrome
What are 4 steps that occur in a tumor in order for it to spread?
- down regulation of E-cadherin
- cells attach to laminin and destroy BM
- cells attach to fibronectin in ECM and spread locally
- entrance into vascular or lymphatic spaces allows for metastasis
What is the role of cadherins?
Keep epithelial cells attached to each other
-gets downregulated by tumor cells in order to detach and spread
What happens to a cancerous cell after it detaches from the neighboring epithelial cell?
it attaches to the laminin in the basement membrane
What happens to a cancerous cell after it detaches from the neighboring epithelial cell?
it attaches to the laminin in the basement membrane
What happens to cancerous cells after it attaches to laminin?
Develops ability to make collagenase that destroys collagen type IV. Destroys basement membrane and then can travel to ECM where it attaches to fibronectin to spread locally to a BV or lymphatics
