module 3: neoplasms Flashcards
what are the two main characteristics of tissue growth and repair?
- cell proliferation
- cell differentiation
what is cell proliferation?
new cells replacing old ones
what is cell differentiation?
cells acquiring the characteristics of the tissue that they make up
what happens to cell proliferation and differentiation in neoplasia?
one or both of these characteristics are lost
describe benign tumors
- not problematic until cause local issue
- have lost the ability to control proliferation BUT:
- growth is slow, may come to a stop
- made of fairly well-differentiated cells and well-organized stroma
- do not invade beyond their capsule
- no metastasis
- generally named for the tissues from which they arise
- can still be a problem if the growth interferes with function of surrounding tissue or inappropriately produced hormones
describe malignant tumors
- AKA cancer
- loss of differentiation (anaplasia) and tissue organization
- cells are different sizes and shapes (pleomorphic)
- lack of a capsule = invasion of nearby blood vessels, lymphatics, and surrounding structures
- most deadly = the ability to spread far beyond the tissue of origin (metastasize)
- carcinoma = from epithelial tissue
- sarcoma = from mesenchymal tissue
- lymphomas = from lymphatic tissue
- leukemias = from blood-forming cells
- solid or hematologic tumours
Define metastasis
cells take over good things from tissue
- spread far beyond the tissue of origin
Despite losing control of proliferation, there are characteristics of benign tumors that distinguish them from malignant growth. Describe these 4 features
- growth is usually slow and may come to a stop
- made of fairly well-differentiated cells and well-organized stroma
- do not invade beyond their capsule
- no metastasis
Can benign tumors still cause problems? How?
yes, if the growth interferes with the function of surrounding tissue or inappropriately produces hormones
Describe 4 characteristics of malignant tumors
- loss of control of growth
- anaplasia = loss of differentiation
- can invade local tissues
- can metastasize = spread beyond the tissue of origin
what is anaplasia?
loss of differentiation
what is pleomorphic?
cells are different sizes and shapes
How are benign tumors named compared to malignant tumors?
benign generally named for the tissue from which they arise, with suffix “oma”
malignant tumors are named for cell type from which they originate with
What does “adeno-” at the beginning of a name mean? From what tissues do lymphomas originate from? Leukemias?
- “adeno-” = pertaining to a gland
- lymphomas originate from lymphatic tissue
- leukemias are cancers of blood forming cells
Describe the two categories of malignant neoplasms
- solid tumors (initially confined to specific tissue/organ)
- hematologic tumors (cells normally found in blood/lymph)
Most human cancers are derived from which tissues?
epithelial tissue
Describe “carcinoma in situ”. Where can this occur?
- a growth with malignant characteristics in epithelial tissue that has not (yet) invaded local tissue.. technically not malignant
- hard to decide either to treat or watch it
- can remain stable, become malignant, or regress
- occurs:
- breast
- cervix
- skin
- stomach
what are eight cancer cell characteristics?
- genetic instability
- the cell must become independent of external growth signals
- loss of contact inhibition
- decrease in cell adhesion
- loss of anchorage dependence
- production of unusual antigens
- able to divide without limit
- altered metabolism, increasing anaerobic respiration
describe genetic instability
a high frequency of mutations in cancer cells
describe how the cell must become independent of external growth signals
- able to make their own signals
- don’t need any signals
- extremely sensitive to growth factors
describe loss of contact inhibition
normal cell usually stop growing once they come in contact with each other, but cancer cells will keep on growing and pile up on top of each other
describe a decrease in cell adhesion
normal cells have membrane structures that allow them to stick together
cancer cells lack that ability= can more easily be shed from a tumour = increase chance of metastasis
describe loss of anchorage dependence
cancer cells can survive and grow under conditions that normal cells can’t
describe the production of unusual antigens
there is a production of wonky markers and it is harder to control those cells
describe the ability to divide without limit (immortal)
- telomeres are ends of chromosomes that get shorter each cell division, until. the cell can’t divide anymore
- cancer cells have an enzyme called telomerase = lengthen telomeres = cells divide without a limit and immune system thinks it’s ok
describe an altered metabolism, increasing anaerobic respiration
cancer cells do not undergo very much cell respiration = don’t need a lot of o2, goes throuh anaerobic resperation
Explain why cancer cells require such high levels of glucose
because they use mainly anaerobic respiration (glycolysis) = normal tissue starts to die off
How do we use this characteristic (high levels of glucose) to detect cancer cells in the body?
use a fluorescent compound that is taken up by cells in the same way as glucose, but can’t be metabolized
- accumulates in cells that would take up a lot of glucose
What is metastasis?
- metastasis: the spread of cancer cells from the original site to distant organs and tissues
Describe the local growth of benign tumors
- local spread = helped by enzymes made by the cancer cells that break down cells and connective tissue of surroundings (crablike extensions)
- benign = pushed on surrounding connective tissue to form a capsule around the growth
describe the difference in the local growth of malignant tumors to explain why malignant tumors metastasize
malignant tumors = cells that grow uncontrollably and spread locally and/or to distant sites
- because they are not in a capsule and they have lost their cell proliferation & differentiation
Carcinomas spread through ______________, while sarcomas spread through the ______________.
- lymph
- blood
describe the spread of carcinomas
- through lymph
- the tumor cells lodge first in the initial lymph node that drains the area (AKA sentinel node)
- goes through the lymphatic system - drains through node where cancerous cell shows up
- examination od these nodes can show if metastasis has occured
describe the spread of sarcomas
- spread through blood
- the organ that is next in the vascular pathway is most likely affected
- OR organ that supplies a similar environment as the tissue containing the original tumor
Describe the steps in metastasis
must evolve characteristics needed to metastasize
- initially invade the interstitial spaces of local tissue
- if carried by lymphatic drainage, go to primary or sentinel lymph nodes
- enter the venous system as lymph drains into left and right subclavian veins
- must evade the innate immune system
- secrete proteolytic enzymes to penetrate tissues from blood vessels (vice versa)
- once “seeded” release cytokines and growth factors that control invaded tissue functions
- stimulates their growth and proliferation
- cancer must develop ability to perforn angiogenesis
what are seven possible local effects of a tumor?
- compression
- obstruction
- infarction
- hemorrhage
- rupture
- effusions
- effects are usually combined and relate to symptoms
describe a compression local effect of tumors
loss of function, sensation
- ex: brain tumor, headaches, local nerve compression
describe an obstruction local effect of tumors
growth is blocking the way
- ex: blockage to airways, gut
describe an infarction local effect of tumors
obstruction of blood vessels
- casing local necrosis of tissues
- ex: blood in stool from colorectal cancer
describe a hemorrhage local effect of tumors
severe bleeding out of blood vessel
- ex: intestine, lungs