Cancer Flashcards
What is the definition of cancer according to
the World Health Organization?
Large group of diseases, can start in almost
any organ or tissue of body when abnormal cells grow uncontrollably, go beyond their usual boundaries to invade adjoining parts of the body, and/or spread to other organs.
Second leading cause of death globally, accounting for an estimated 9.6 million deaths, or one in six
deaths, in 2018.
What are the most common types of cancer in males according to the World Health Organization?
Lung, prostate, colorectal, stomach, & liver cancer
What are the most common types of cancer in females according to the World Health Organization
Breast, colorectal, lung, cervical, & thyroid cancer
What is Parenchyma?
Functional tissue of tissue/structure/organ, i.e.,
group of cells that are performing the tissue’s work
What is Stroma?
Connective tissue or supporting tissue of a structure
or organ
What roles can the Stroma play?
˃ container role: outer membrane that encloses the
structure’s parenchyma)
˃ structural role: supports/reinforces the structure’s
shape and tissue integrity
˃ protective role: can help protect the tissue cells
˃ attachment role: component that attaches the structure to others (e.g., tendinous attachment to bone)
˃ term technically also includes all parts that do not perform functions of the structure (blood vessels, ducts, etc.)
(Stroma Roles) What is the container role?
Outer membrane that encloses the structure’s parenchyma)
(Stroma Roles) What is the structural role?
Supports/reinforces the structure’s shape & tissue integrity
(Stroma Roles) What is the protective role?
Can help protect the tissue cells
(Stroma Roles) What is the attachment role?
Component that attaches the structure to others (e.g., tendinous attachment to bone)
What is Cell Proliferation?
Process by which cell populations are maintained in tissue or structure. Most cells are produced, mature, do their work, & die from injury/disease, internal process, or age. With most cell types, dead cells are replaced by replication of neighbour cells.
What are Labile Cells?
Cells that continuously divide & regenerate, typically found in areas like skin, gut lining, & bone marrow. Their constant division helps maintain & repair tissues.
What are Stable Cells?
Cells that divide only when needed, typically during tissue repair after injury. Usually in resting state but can re-enter cell cycle if necessary. Eg. liver cells (hepatocytes) & kidney cells. Unlike labile cells, they don’t divide constantly but have potential to regenerate when required.
What are Permanent Cells?
Cells that don’t divide after they have fully matured. Once damaged, they cannot regenerate or be replaced by new cells. Eg. include neurons (nerve cells) & cardiac muscle cells. If injured, these tissues heal through scarring rather than cell regeneration.
When cells are lost, normal ways of maintaining cell population in a tissue or structure include?
Boundaries: Cells stop replicating when tissue-defining structures (e.g., basement membrane) are filled.
Cell-Cell Controls: Chemical signals regulate cell replication, growth, & apoptosis.
What role do boundaries play in cell population control?
Cells stop replicating when they reach physical boundaries like the basement membrane, preventing overgrowth.
How do cells communicate to maintain population size?
Cells send chemical signals to sense cell depletion or overpopulation, which either stimulate or suppress cell replication, growth, or trigger apoptosis.
How does the body prevent overpopulation of cells?
Chemical signals turn off once normal cell population is reached, mitigating against excess cell growth.
What factors are involved in controlling cell populations?
Chemical signals that can stimulate or suppress:
- Cell replication
- Cell growth
- Apoptosis (programmed cell death)
What does autophagy (autophagocytosis) mean?
It means “eating of self.”
What is the primary function of autophagy?
It’s a normal, orderly process that disassembles damaged, excess, or dysfunctional organelles, making their building blocks available for reuse.
How does autophagy contribute to cellular health?
It promotes cell health & function & recycles cellular components, acting as a homeostatic process.
What role does autophagy play in cellular housekeeping?
It eliminates poor-quality/damaged cellular components & intracellular toxins/pathogens.
When is autophagy increased?
It increases during cellular stress & starvation conditions to prune organelles & reduce energy expenditure.
How does autophagy occur within the cell?
Targeted elements are isolated into a double-membraned vesicle called an autophagosome, which fuses with a lysosome to degrade its contents. Useful components are recycled.
What are some complex roles of autophagy beyond its basic function?
It promotes cell surface antigen presentation, protects against genome instability, prevents necrosis, & promotes cellular senescence.
How does autophagy relate to disease prevention?
It is involved in preventing diseases such as cancer, neurodegenerative conditions, heart failure, diabetes, liver disease, autoimmune diseases, & infections.
What is known about the regulation of autophagy?
It is a highly regulated process that has received increasing attention for its complexity.
What happens when autophagic processes become abnormal?
They can promote cellular disorder & death, contributing to disease.
How does reduced autophagy affect aging?
Inefficient autophagy can lead to less healthy conditions within cells, allowing pathological changes & paving the way for disease states.
What is apoptosis?
Apoptosis is programmed cell death, triggered within the cell under certain conditions (e.g., old, unwanted, or unhealthy cells).
What happens to most cells regarding replication?
Most cells have a finite number of replications and undergo apoptosis when that limit is reached.
What are some examples of excess tissues eliminated by apoptosis?
Webbing between fingers in utero, excess neurons & synapses in the brain, & thymus tissue over time.
What types of internal cell damage can initiate apoptosis?
Damage from viral infections, oxidants/free radicals, UV light, cancer-causing factors, & some autoimmune processes.
How does apoptosis help prevent cancer?
It eliminates damaged cells, thereby reducing the risk of genetic mutations that could lead to cancer.
What happens once apoptosis is initiated?
Proteins called CASPASES break down DNA/chromatin, the nucleus deconstructs, & the cell shrinks, forming BLEBS & releasing chemicals to attract macrophages.
What are apoptotic bodies?
Remnants of the nucleus & cytoplasm that are bundled into membrane-bound blebs, which are later cleared by phagocytic cells.
What are the consequences of excessive apoptosis?
Too many cells are killed, leading to serious tissue damage/loss (e.g., in Alzheimer’s Disease & Parkinson’s Disease).
What happens when there is insufficient apoptosis?
Cells that should be eliminated become resistant to death, contributing to conditions like cancer.
How do genetic mutations affect apoptosis in cancer?
Many cancers have genes that block apoptosis initiation, making them treatment-resistant despite DNA damage.
What are scientists seeking to understand about apoptosis?
They aim to better understand the signals that initiate apoptosis for potential therapeutic applications.
What are blebs?
Outpouchings of the membrane
What is cell differentiation?
The process by which stem & progenitor cells evolve into mature, functioning tissue cells.
What are progenitor cells?
Cells that are a stage between stem cells & differentiated cells, essential for developing various tissue types.
What happens to cells once they are specialized (differentiated)?
They cannot revert to stem or progenitor status.
What role do stem cells play in adult tissues?
They act as a repair system, replenishing specialized cells & maintaining tissue populations.
Which tissues have a larger role for stem & progenitor cells?
Blood, skin, & endothelial lining membranes.
What is tissue dystrophy/atrophy?
A temporary or permanent decline in the number and size of cells in a tissue or structure.
What is hypertrophy?
Increased size of parenchymal cells in response to increased workload, e.g., in muscles or glands. It can reverse if conditions change.
What is hyperplasia?
Increased number of parenchymal cells in response to higher needs, such as in breast tissue during pregnancy or the formation of skin calluses.
What defines normal hyperplastic changes?
They remain under normal tissue proliferation guidelines, like breast tissue changes during lactation.
What are some examples of dysfunctional hyperplasia?
Unusual breast growth in males due to hormonal issues, prostate hyperplasia related to aging, & abnormal tissue accumulation from chronic inflammation.
What is metaplasia?
The replacement of a mature differentiated cell type with another mature, differentiated cell type that is more resilient under stress.
