Cancer Flashcards
Cancer
Abnormality in cell _____, ______, and/or cell _________
A disruption of cellular _______
A disruption in the normal functioning of _____ ______ genes =
- Cells in our body are under a tremendous amount of ______ - a fascist society
- Cancer is a ______ of those genes
growth, division, differentiation
cellular societies
social control genes any gene that codes for a protein that is involved in cell growth, divsision, and differentiation
- control
- disruption
Social Control Genes
direct, stimulate, inhibit, or regulate
(6)
Cell Division
Cell Differentiation
Cell Growth
DNA repair
Cell mortality (# of times a cell can divide)
Apoptosis (programmed cell death/suicide)
Four Phases of Pathogenesis and Spread
(4)
Transformation
Growth of Transformed Cell
Local Invasion
Distant Metastasis
Transformation
=
Growth of Transformed Cell
=
Altered growth-proliferation control (on genetic level) - normal host cell transforms into a malignant cell (oncogene) from a mutation in a social control gene (not every mutation is going to produce cancer, transformation of cells is not uncommon but the continued growth is fairly uncommon, immune system usually kills it
Tumor formation - proliferation of malignant cells into a tumor
Local Invasion
=
Distant Metastasis
=
Direct extension Metastasis
Invade surrounding tissue and creation of own blood supply (cancer cells will not just invade but eats a hole through whatever it encounters)
Cells break free from tumor colonize distant sites
Same tumor just grows into a neighboring organ
The Cell Cycle-Phases of Cell Division
- G1:
- S:
- G2:
- Mitosis:
- Cells are getting ready for DNA replication (most cells in this stage)
- Cells actively replicating DNA
- Cells making copy of its intracellular material and proteins - final phase before cellular division
- Cellular division (starts with nuclear division and ends with cytoplasm division)
Common Targets of Potential Mutations
-
Cell Cycle Inhibitors =
- Some of these really powerful inhibitors (1) are the common genes mutated in cancer -> don’t get tonic inhibition
-
DNA repair proteins =
- (2) examples that if mutated dramatically increases lifetime risk of (3) types of cancer -> at the heart of it is all about the loss of DNA repair
- like breaks at every stage that prevents cell from moving onto next phase, the genes that code from them are notoriously oncogenes
- Master breaks (doors with triple locks)
- Designed to identify potential mutations, can sometimes repair it themselves or trigger apoptosis if too many errors detected
- BRCA 1/BRCA 2, breast, uterine, ovarian
Increased risk for mutuation leading to malignancy with more cell division/replication
Phases of Mitosis
What phases of Mitosis of the cell cycle are the easiest to visually identify histologically? Why?
- Takeaway: you _____ see normal cells in any phase of mitosis, most cells are in the ___ phase
- Rate of cell division: # of cells in active division is part of assessment of how _______ the cancer can be
-
Nondividing cells (2): are all strongly frozen in the ___ phase
- Ex) Brain tumors are never of ______ origin, usually ____ cells
Metaphase (chromosomes being lined up) and Anaphase (chromosomes pulling apart) -> patholgist can see alot of cells are in active mitosis in tumors
- rarely, G1
- aggressive
- neuronal, myocytes, G0
- neuronal, glial (glioma, astrocytoma)
Cell Differentiation
- With every differentiation step
- Fate of the cell _____
- _____ activity starts to _____
-
Terminally differentiated cell =
- Ex) ______ ______ cells: terminally differentiated cannot handle damage from smoking and get replaced by newly differentiated simple squamous so now you lose cilia that helps to clear mucus and you get a cough and mucus buildup
- With every differentiation step
- narrows
- Mitotic activity declines
- most functionally mature and lost it’s ability to divide
- Ciliated Columnar Cells
Example of differentiation. Differentiation occurs several times in the lifetime of a granulocyte, with each step further limiting the cell’s potential. Eventually the cell terminally differentiates and can no longer divide, and the mature cells die.
Cancer Cells Resist Differentiation
-
____ differentiated tumor cells = more aggressive cancer bc very ______ active and contribute least to the _____ of the tissue and create more problems for the pt
- Ex) ______ = over-proliferation of highly undifferentiated rbcs, wbcs -> anemia, immunodeficiency bc wbc are malignant and don’t work
-
Less differentiated = more aggressive, mitotically active, contributes least to function
- Leukemia
Cell Differentiation
- Normally, stem cells first divide then?
- What happens in the pattern of potential tumor formation?
- What is a common cell type to become cancerous bc it is rapidly dividing all the time?
-
Characteristics of Malignant cells
- ____ rate of unregulated cell ______
- ______ to differentiation
- half of the daughter cells will go on to differentiate
- When more than half of stem cells remain stem cells and refuse to differentiate
- Epithelial tissue
-
Characteristics of Malignant cells
- High rate of unregulated cell division
- Resistance to differentiation
Differentiation of a stem cell. A, When a stem cell divides, each daughter has a choice: it can either remain a stem cell or go on to become terminally differentiated. B, this pattern of cell renewal and proliferation of stem cells in the epithelium forms the lining of the small intestine
Cancer Cells
The transformation of a cell into a cancer cell involves a mutation in a ______ ______ gene to form an ______.
- (1) = promotes normal cell division or growth
- Mutation causes ______ of gene ->Oncogene -> promotes cancerous cell growth
-
(1) = limits normal cell division/growth or promotes cell differentiation/cell death
- Mutation causes _____ of gene -> Oncogene ->promotes cancerous cell growth
- Nearly every hereditary cancer is linked to what type of gene?
mutation in social control gene ->oncogene
-
Proto-oncogene
- Hyperactivity (turned on to promote cell division through growth factors and cytokines)
-
Tumor-suppressor gene
- Inactivity (ie BRCA 1/2 so can’t limit formation)
- Tumor suppressor gene
Two Routes of Mutations that produce Oncogenes (notes)
- (1): purple side - growth factors, receptor for growth factors, inside the cell has intracellular signaling proteins, and transcription factors that the growth factors work through
- (1): blue side - cell cycle inhibitor or potentially a cell differentiation stimulator- has receptors and intracellular signaling proteins, and transcription factors
- Wide variety of potential targets for development of proto-oncogenes for these growth factors and tumor suppressor genes
- Stimulatory Route
- Inhibitory Route
Pathways of Mutation
Genetic mutations can cause cancer. Genetic mutations cause ______ pathways (purple) to tissue too many “__ signals” or ______ pathways (blue) can no longer issue “___ signals”.
A stimulatory pathway will become _____ if a mutation (ie. oncogene) causes any component, such as a ____ factor receptor (box at left) to issue stimulatory messages autonomously without waiting for signals from upstream. Conversely, _____ pathways (e.g., mutations causing tumor-suppressor genes) will be shot ____ when some constituent, such as cytoplasmic relay (box at right), is eliminated and thus _____ the signaling chain
stimulatory, “go signals”, inhibitory “stop signals”
hyperactive, growth
inhibitory, shot down, breaks the signaling chain
Mechanisms for Abnormality-Targets of Oncogenes
Aspects of cell function under social control and therefore possible mechanisms for cancer disruption
- _____ transduction
- Cell _____ control
- DNA _____
- Cell ____
- Cell _______
- ________ regulation
- S_____
- A_______
- Signal transduction
- Cell cycle control
- DNA repair
- Cell growth
- Cell differentiation
- Transcriptional regulaiton
- Senescence
- Apoptosis
Targets of Oncogenes
- Cell Cycle Control =
- Transcription factors =
-
Senescence =
- Immortalized cell =
- cell cycle inhibitors or stimulators that are potential targets
- proteins that control whether a gene gets expressed or not (they are inside the nucleus at the lvl of DNA and bind to promoter regions of a gene to determine whether it gets transcribed or not)
- the limit that any cell in our body has to the number of cell divisions it can undergo (usually about 50-60 times) - its mortality
- when they continue to divide past beyond that point - capable of passing on genome in an unlimited way
Known Proto-Oncogenes and Tumor Suppressor Genes
3 important/common tumor suppressor genes
- P53 protein =
- RB protein =
- DNA repair protein (2)
- Subcellular location and functions of major classes of cancer associated genes
- red =
- blue =
- green =
- purple =
- coded by p53 gene and expression of P53 also increases as the number of errors on DNA are identified by the cell -> inhibition of cell cycle gets stronger as the cell notices ore errors on DNA -> once amount of p53 hits a critical point -> triggers apoptosis
- Half of all tumors have mutations in P53 gene
- coded for RB gene, stands for retinoblastoma bc first identified in that cancer type, also a common mutation in all types of tumors, a massive cell cycle regulator (doors in the cell cycle) if mutated will free the cell to divide as much as it wants
- BRCA 1/2
- proto-oncogenes (normal genes that regulat growth and differentiation)
- cancer suppressor genes
- DNA repair
- genes that regulate Apoptosis
Basic Properties/Behaviors of Cancer Cells
Autonomy and Anaplasia
- (1) Cancer cells _____ despite lack of _____-initiating signals from the environment
- Cancer cells _____ signals to die (turn off signals for apoptosis) and achieve a kind of ______ in that they are capable of unlimited ______
- (1)Cancer cells lose their _______ features and contribute poorly or not at all to the _____ of their tissue
- Cancers cells are _______ unstable and evolve by accumulating new ______ at a much faster _____ than normal cells
- Cancer cells ____ their local _____ and _____ their neigbors
- Autonomy: proliferate, despite lack of growth initiating signals
- escape signals, immortality, unlimited replication
- Anaplasia: lose differentiated features, contibute poorly to function
- genetically unstable, accumulate mutations, faster rate
- invade local tissue, overrun their neighbors
Cell Mortality and Senescence
Normally cells can divide (double) about __-__ times before growth shuts off (1)
->
Some escape (1) and keep dividing. Eventually these cells will reach (1) and start dying off in large numbers
->
Cells that manage to escape Senescence and Crisis have acquired some _____ that has (1) them
50-60 times (Senescence)
Senescence, Crisis
mutatio, Immortalized
Telomeres
=
Everytime DNA replicates, telomeres get?
Like the plastic tips on shoelaces, without it ends of DNA would separate and fray and become vulnerable to mutation
Shorter
Telomerase Enzyme
=
What happens to the telomerase enzyme over time?
Function is to rebuild telomeres
A cell’s ability to produce telomerase progressively declines with greater # of cell divisions -> finally can’t rebuild telomeres -> errors accumulate along terminal protions of that DNA -> DNA repair proteins will bind to those errors and block cell division = senescence
Control of Replication
- So for cells that escape senescence -> continue to multiply and all of those daughter cells have lots of _____
- One protein that starts to get expressed when the cell finds errors (1) -> then when there’s enough of this P53 -> _____ = ______
- So if there’s a problem w P53 or DNA repair it can also become ______
- Ans: Cell’s ability to overexpress telomerase enzyme = can in an unlimated way keep repairing its telomeres and continue to double = ____-_____
- errors
- P53 -> Apoptosis = Crisis
- immortalized
- Proto-Oncogene
Structural and Functional Changes in Cancer Cells
(4)-(2)
Cytoskeletal Changes
Changes in Cell Adhesion/Motility
- Role of Fibronectin
- Implication for Density dependent growth
Nuclear Changes
Enzyme Production
Note: CEA = carcinoembryonic antigen, AFP = alpha-fetoprotein
Cytoskeleton Changes in Malignant Cells
=
Amorphous, globular, irregular shape dt disorganized cytoskeleton
Gets disassembled when the cell mitotically divides and cancer cells have high mitotic rates
Nucleus Changes in Malignant Cells
=
Disorganized/amorphous shape again dt high mitotic rates
Chromatin and chromosomes are unwinding and are in some stage of DNA replication and division
Cell Adhesion Molecules in Normal Cells
Fibronectin =
Density Dependent Growth =
normal cell adhesion molecules that anchor one cel to the neighboring cell -> helps maintain the integrity of tissue and regulates density dependent growth
By being physically connected to your neighbors, you know how many neighbors you have which tells you the density of that tissue and when it reaches optimal cell density -> will shut off replication and division
Cell Adhesion Molecules in Malignant Cells
=
- How does this effect their growth?
- How does it effect their spread?
- Ex (1)
Cancer cells often lack adhesion molecules including fibronectin
- Don’t care what the density of the tissue is, does not control their growth
- Also means that cancer cells are not anchored to one another and makes them more mobile -> can shed off of a tumor
- Ovarian CA most commonly from the external epithelial lining of the ovaries so the way they spread is just by falling off into pelvic cavity (only symptoms will be bloating/pain and not found till later stages)
Oncogenic Viruses
Direct Mutagenesis =
- Example (1)
Indirect Mutagenesis =
- Example (1)
When a virus infects a specific tissue bed, gets inside the cells and use it to replicate the virus -> viruses that in the process of infecting the host cell inserts an oncogene into the host cells genome and gets propagated, transforms cell into a cancer cell
- HPV
Virus infects and attacks a tissue bed and contributes to a lack of immune regulation that would normally catch a mutation -> so viral infection is preventing immune system from being able to recognize transformed malignant cells
- Kaposi Sarcoma in AIDS
Transformation by Altered Genetic Changes
Stimulus (initiator) causes genetic mutation (oncogenes and tumor suppressor genes) ->
Altered genes for
- ______ factors
- _____ factor receptors
- Signal communication (t_____)
- T_____ regulation
Transformed cell proliferates with abnormal and ______ regulation of growth as a result of genetic changes ->
Tumor
- Growth factors
- Growth factor receptors
- Transduction
- Transcription
autonomous
Benign Tumor
= ___invasive and doesn’t have potential for rapid ____, ___ aggressive - usually just an _____ of ____ tissue
- Often fully _______ and doesn’t ____ surrounding tissue, just ______ it
- Ex) Uterine _____, picture is a classic _____
= noninvasive and doesn’t have potential rapid spread, not aggressive, usually just an overgrowth of original type
- encapsulated, does not invade, just displaces
- fibroids, lipoma
Malignant Tumor
= ______ borders, has eaten away to the skin (_____ of skin that doesn’t heal), doesn’t displace surrounding tissue but ___ away at it
- Area of _____ is common bc often the accumulation of mutations increases the likelihood that tumor cells will eventually die
- Highly _____
- Invading local _____ or ____ vessels
- That’s why usually when tumors are biopsied the (1) is also biopsied
= irregular borders, ulceration, eats
- necrosis
- vascularized
- lymphatic, blood
- sentinel
Angiogenesis
=
Stimulated by chronic low lvl _____ to tissue bed -> angiogenic factors such as (1) stimulate nearby blood vessels to sprout new branches, serve as routes of transport of _____ into the tumor
Tumor creating its own blood vessels
ischemia, FGF fibroblast growth factor, nutrients
Common Proto-Oncogenes Chart
Common Tumor-Suppressor Genes Chart
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Skin Cancer
Most common types (2)
Both almost always grow by _____ invasion and _____ metastasize
Sometimes the skin cancer is malignant ______ (derived from melanocytes)
Melanomas are far more _____ and often _____ to lymphatics and blood stream
Squamous cell carcinoma, Basal cell carcinoma
local, rarely metastasize
melanoma
more aggressive, often metastasize
Skin Cancer Melanomas
- A =
- B =
- C =
- D =
- Asymmetry - when half of the mole does not match the other half
- Border - when the border (edges) of the mole are ragged or irregular
- Color - varies throughout
- Diameter - if the mole’s diameter is larger than a pencil eraser
Lung Cancer
Nearly all cancers arise from cells in the _____
Histologically - most lung cancers are _____ cell carcinomas, _______, and undifferentiated carcinomas of both ____ and ____ cell type
These cell types have characteristic patterns of spatial distribution:
- Squamous and small cell undifferentiated - most frequently arise centrally near the ______
- Adenocarcinomas are usually ______ tumors
All of these cell types behave as ______ tumors
Since the lungs are rich in lymphatic and vascular supply - there are frequent lymphatic and hematological ______
bronchi
squamous, adenocarcinomas, small, large
- mediastinum
- peripheral
aggressive
metastasis
Colon Cancer
- Histologically - tend to be mostly ________
- Arise mostly in (2) parts of the colon
- Some are colorectal ______ arising from bowel mucosa
- Often seen spread to _____ and ______
- If cancer gains access to portal circulation will often see _____ involvement
- Other common secondary sites include ______ metastases
- adenocarcinomas
- distal colon and rectum
- carcinomas
- lymphatics and vasculature
- liver
- pulmonary
Breast Cancer
- Usually an ______ of the ducts of the ______ glands
- This cancer is often _______ sensitive
- Occurs more often in the _______ period (ie after pregnancy and breastfeeding) and appears to be related to prolonged ______ stimulus
- Metastasis to the mammary ______ occurs often but likelihood depends on size and position of the tumor within the breast
- ______ metastasis occurs frequently due to lymphatic spread
- (1): LN closest to cancer in this case is the _____ node
- adenocarcinoma, mammary
- hormonally
- perimenopausal, estrogenic
- lymphatics
- Distant
- Sentinel: axillary
Cervical Cancer
- Typically affects _______ women (approaching _____)
- 95% is _____ carcinoma
- Usually grows via _____ extension and invasion
- With advanced disease can get direct invasion of the _____ and more unusually the _____
- Often spreads to regional _____
- Distant metastases are unusual but when they occur they usually involve the ____ or _____
- perimenopausal - approaching menopause
- squamous
- local
- bladder, rectum
- lymphatics
- lung or liver
Endometrial Cancer
- Occurs only in ____menopausal patients
- 90% are _________
- Mostly grow centripetally _____ the uterine cavity and usually stay _____ to the uterus
- May sometimes grow through the uterine lining to the _______ and underlying lymphatics and vasculature
- Distant metastases are _____ but can occur
- postmenopausal
- adenocarcinomas
- toward, confined
- myometrium
- rare
Prostate Cancer
- Are almost all ________
- Initially tumor spreads by _____ invasion - it eventually penetrates the prostatic capsule and invades the (1)
- It also commonly spreads to (1) in the pelvic region if tumor is close enough
- And can also commonly spread to the (1) if close enough to the vessels in that region
- adenocarcinomas
- local, seminal vesicles
- lymph nodes
- vasculature
Liposarcoma
=
It is a lipogenic tumor of large deep-seated connecive tissue spaces.
_______ are common, especailly in poorly differentiated liposarcomas. (2) most common sites.
Malignancy of fat cells
Metastases common - lungs and liver
Primary Brain Tumors
A unique form of tumors
- None of the various types arise from neuronal cells bc they are?
- They usually arise from supportive cells like (2)
- Most tumors are _______
- Brain tumors grow almost entirely by _____ invasion
- LN metastases? Distant mets?
- non-dividing, non-proliferating
- astrocytes (astrocytomas), glial cell (gliomas)
- astrocytomas
- local
- no, very rare
