INP final - CANCER Flashcards
Flashcards for the second half of the INP course. This set will cover CANCER
What is epithelial tissue?
- Epithelium, specifically the epithelial cells, line body surfaces
- Function to cover line and protect surfaces
- absorb things within the intestine and secrete things through the epithelial cells of glands
- they do not contain blood vessels, nutrients pass through the basement membrane
- faces the extracellular matrix which contains the connective tissue, glands, and blood vessels (epithelium does not contain blood vessels but nutrients pass through the basement membrane)
What does epithelium look like?
- Layer that can be simple, or stratified in layers
- Cells can either shaped and be squamous (flat), cuboidal, and columnar
- Can be specialized- junctions, cilia, microvilli
Sealing -> tight junctions
Adhering -> desmosomes, adherins
Communicating -> gap junctions
Types of epithelium.
- Simple columnar – lining of the intestine (contains microvilli which increases SA)
- Simple squamous – blood vessels
- Stratified squamous – skin, esophagus
What is polarization of epithelium?
Basal and apical side have different functions (basal means to go to blood vessels and apical means exocrine so that side has molecules that are going to secrete into the free surface/has an absorptive function)
polarization means that it allows cells to have secretion and absorption in compartments and allows cells to interact with extracellular matrix at special points of contact so the cell could know what function it has since it has proteins on the membrane
Cancer cells LOSE polarity
What is the purpose of the extracellular matrix (ECM)?
- determines the type of tissue that are there, tells the cells how to move and interact (produced by tumor cells)
- Provides the environment for the cells to live in
- Contains fiber (collagen and elastin support), ground substance (holds water in tissue) and cells (produce the ground substance
- Necessary for tumor survival
What are some environmental causes of cancer?
DIET RELATED (i.e. nitrates, H. pylori)
- aflatoxins in wheat
- hepatitis B
- changes in migration/moving
OBESITY
- Obesity (due to level of inflammation)
- smoking
- alcohol
- reproductive history (unopposed estrogen without progesterone increases risk)
- infection
What is a benign neoplasia and its histological features?
- end in “omas”
- localized to one are and cannot spread to other sites, surgical excision is possible and arises from a single mutation with a growth advantage (does not have a mutation pattern)
- well circumscribed, usually encapsulated meaning that it cannot invade or spread to other sites, contains cell polarity, does NOT go through the basement membrane
- small, uniform cells, NO visible nucleoli, 1:1 nuclei to cytoplasmic ratio
- most patients survive but some tumor locations can cause serious problems
- SLOWER growth, some are dependent on hormones WELL differentiated (how different the cells look like the one it came from) resembles cell of origin with FEW mitoses, secretion of products, hormones, mucins because of maintained cell polarity
What is a malignant neoplasia and its histological features?
- can invade and destroy adjacent tissue and spread to distant organs (metastasis) to cause death (has a mutation pattern that allows for it to go through the basement membrane of the epithelium and the epithelium of the blood vessel)
- poorly circumscribed, LACK of cell polarity and epithelial cell connections, not encapsulated so it can invade
- large, pleomorphic cells (ability of some micro-organisms to alter their shape or size in response to environmental conditions) with large hyperchromatic nuclei, higher nuclei to cytoplasmic ratio, large nucleoli, irregular nuclear outlines meaning that cells are different sizes, shapes and not aligned on the basement membrane
- more rapid growth, areas of necrosis (cell death) due to lack of adequate blood supply
- well to poorly differentiated with numerous, bizarre mitoses
What is dysplasia?
- Disordered cellular maturation where cells do NOT mature (no base to surface
NO polarity) due to the inhibition of tumor suppressors by viral proteins to regulate the cell cycle -> cells at the base, because that is where the nuclei are located, are rapidly dividing and growing that they “forget” to mature -> inhibition of tumor suppressor proteins in the cell lead to neoplasia -> inhibition of the tumor suppressors lead to big nuclei - Caused by disruption, mutation and inhibition of normal cell molecules that regulate cell cycle and cell division.
- Commonly seen in HPV in the cervix, smoking in the respiratory tract, and GERD in the esophagus
What is metaplasia?
- Change from one type of epithelium to another due to injury/damage that leads to eventual proliferation and cancer (this conversion is permanent)
- Can be caused by smoking which impacts the squamous metaplasia in respiratory epithelium which leads to proliferation and cancer
What are the steps to successful metastasis?
1) Detachment of tumor cells (E-Cadherin) by loosening junctions
2) Degradation of ECM (MMP’s are overexpressed and TIMP’s reduced)
3) Attachment to new ECM proteins (cleaved collagen and laminin binds to receptors in tumor cells - stimulate migration)
4) Migration of tumor cells (cytokines from tumor cells direct movement and from stromal cells for motility that bind to tumor cells)
What predicts where tumor cells will spread in different cancers?
- Most metastases are predicted by anatomy-vascular and lymphatic drainage
- It is related to expression of endothelial adhesion molecules
- Chemokines and chemokine receptors aid in homing
- After extravasation, tumor cells only survive only in receptive ECM and stroma
What is the connection between obesity/body composition and cancer? What is the presumed mechanism for this association?
- Changes in weight gain lead to changes in biomarkers that are presumed to lead to an increase in cancer risk
- Increases: Bioavailable estrogen, infammatory cytokines, leptin, insulin and insulin related growth factors lead to low grade chronic inflammation
- Decreases: Adiponectin
- Sedentary lifestyle and excess energy intakes and fat intake are attributable to increases in risk of obesity
Explain why physical activity is a recommendation for cancer prevention.
- Physical activity may lead to weight loss and loss of fat stores
- Works even without weight loss
- It leads to increases in beneficial hormones, modulates the immune system and the GI tract; helps avoid weight gain (which increases cancer risk)
- Improves/increases insulin sensitivity and improves/reduces inflammation
- Help avoid weight gain
- Helps with psychological health and stress management
What types of foods are recommended for reducing cancer risk and why?
Decrease/Limit
- Refined carbs: Certain carbs are hypothesized to increase cancer risk by causing spikes in postprandial blood glucose concentrations and circulating insulin -> carbs with a high GI are associated with higher PP insulin and higher fasting insulin
- Ultra-processed foods because it removes some of the nutrients that you need (**important to note that some processing of processed foods can enhance nutrient bioavailability
