Cancer Reading Guide- Mini Exam 4 (09/15) Flashcards
How do we get cancer
environment, cell cycle, and genetics
some environmental agents associated with cancer are:
viruses, tobacco use, food, radiation, chemicals, pollution
types of genes within individual cells which may mutate to cause cancer
oncogenes, tumor suppressor genes, DNA repair genes
somatic mutations
alterations in the function of the DNA repair genes
oncogenes
-genes that regulate cellular growth
porto-oncogenes
normal state
initial state of oncogenes
as proto-genes promote cell growth that is self-regulated
mutation causes genes to become oncogenes, cell growth becomes unregulated
tumor suppressor genes
the genes normal function is to regulate cell division, both alleles need to be mutated or removed in order to lose the gene activity
the first mutation may be inherited or somatic
the second mutation will often be a gross event leading to loss effectiveness of gene
DNA repair genes
genes that detect mutations
normally will send protein to site of mutation and promote repair
mutation will cause slow reaction to mutations or will cause these genes to become dormant
cellular proliferation
the generation of new, daughter cells divided from progenitor (parent cells)
-stem cells play an important role in proliferation
stem cells
- highly undifferentiated
- have potential to divide into daughter stem cells
- can mature into more differentiated units that have a specific function
cellular differentiation
refers to maturity, specificity, and functionality of cells
cellular differentiation normally takes place in an orderly process
three basic steps of cellular differentiation
- cells start out as undifferentiated (stem) cells that have the potential to mature into more specific cell types
- as a need arises the stem cells turn into progenitor (patron) cells that can reproduce daughter cells
- daughter cells then become highly differentiated cells that do not reproduce
most frequent problems with altered cellular proliferation and differentiation
most frequent problems: over-proliferation and lack of differentiation
neoplasia
neoplasia
the irreversible deviant development of cells that result in the formation of neoplasms
where do we see neoplasias
only in cells that have the ability to proliferate (esp. cells that undergo rapid mitosis)
where would we not see neoplasias
permeant cells that do not regenerate are not areas where neoplasia arises
- cardiac myocytes
- mature neurons
- lens of the eye
why does cancer occur
- at the level of the cell, cancer is genetic
- all cancer involves malfunction of genes that control cell functions (reproduction, growth, differentiation, death)
caretaker genes
genes taht repair mutated DNA and protect the genome
oncogenes
genes that code for proteins involved in cell growth and proliferation
tumor suppressor genes
genes that prohibit over-proliferation of cells and regulate apoptosis
what is the path of malfunction
called carcinogens
- initiating event
- promoters (internal and external)
- continued exposure and change in DNA)
carcinogens
cancer causing agent, agents that interfere with molecular pathways and can initiate or promote tumors to form in the body
types of carcinogens
radiation, hormones, tobacco, viral infections, chemicals
characteristics of neoplasms
autonomy and anaplasia
autonomy
unregulated cell growth
anaplasia
term used to describe the neoplasms loss of differentiation
the greater the degree of anaplasia, or the more undifferentiated the tumor cells, the more aggressive the tumor will be
the greater the degree of anaplasia, or the more undifferentiated the tumor cells, the ____ aggressive the tumor will be
more
neoplastic cells
- lack cell-to-cell inhibiitions, cohesion, and adhesiveness
- undergo extensive angiogenesis (development of new blood vessles)
- deprive unaffected tissues of oxygen and other nutrients
- secrete substances that can alter metabolic processes
benign characteristics
- remain localized
- over-proliferate, but do not have significant loss of differentiation
- can still be life threatening
- can sometimes be a precursor to cancer
malignant characteristics
invasive
destructive
spread to other sites
doesn’t resemble tissue of origin (undifferentiated)
can cause ischemia and necrosis of tissue
uses energy and nutrients that are needed by healthy tissue
types of cancer spread
localized, invasion or direct extension, seeding, metastasis
localized cancer spread
proliferation within the tissue of the organ
can still cause: obstruction, hemorrhage, necrosis
better prognosis
invasion or direct extension cancer spread
tumor cells moving and growing into adjacent tissue and organs
travels to nearby structures
releases enzymes that degrades tissue walls that allows the tumor to grow
seeding cancer spread
cancer cells in body fluids or along membranes
occurs many times within peritoneal or pleural cavities surrounding affected organ or tissue
gravity will pull the cells downward or cells will follow flow of fluid within the body cavity
metastasis cancer spread
malignant neoplasms spread to distant sites: lymphatics and blood vessels
lethal aspect of cancer
detection and treatment become much more complex
steps of metastases
- breaks through the basement membrane and/or extracellular membrane
- gains access to and begins to circulate within the blood vessels or lymph system
- leaves the blood vessels or lymph system and adheres to distant tissues
- establishes a new nutrient network through the process of angiogenesis
organ tropism
desire of a primary tumor to relocate to a specific distant site
factos that promote organ tropism
favorable environment for new growth, increased adherence capability, location of the distant organ in relation to the blood flow or lymphatic flow
examples of organ tropism
colon cancer to liver
lung to brain
breast or prostate to bone
-oma
benign tumor sufficiently attached to a root word
carcinomas
cancer of epithelial tissue
adenocarcinomas
cancer of glandular tissue
sarcomas
cancer of connective tissue
leukemias
hematopoietic (blood forming organs)
lymphomas
tumors in lymphatic tissue
gliomas
tumor of central nervous system
carcinoma-in-situ
early stage cancer tumor that has not broken through the basement membrane of the organ
TNM
size of tumor
involvement in the lymph system
metastasis (remember if this one is yes it is automatically stage 4)
grade 1
well differentiated, cancer confined to organ of origin
grade 2
moderately differentiated cells. cells invading locally
grade 3
poorly differentiated cells, spread to regional structures
grade 4
undifferentiated cells, spread to regional structures
systemic effects of malignant tumors
weight loss and cachexia; anorexia, fatigue, pain, stress; anemia; severe fatigue; effusions; infections); bleeding); paraneoplastic syndrome
cachexia
weakness and wasting of the body due to severe chronic illness
CAUTION
Change in bowel/bladder A lesion that doesn't heal Unusual bleeding or discharge Thickening or lump in breast or elsewhere Indigestion Obvious change in wart or mole Nagging cough or persistent hoarseness
Diagnostic tests
routine screening self-examination blood tests radiographic, ultrasound, MRI, CT scans Cytologic tests require biopsy or cell sample
routine screening tests
essential for early detection
following treatment to detect any further tumors
self-examination tests
early detection if done consistently
breast, testicular, and skin exams are important
blood tests
measure blood cell levels during treatment, may detect tumor markers eg PSA test
radiographic, ultrasound, MRI, CT scans
methods of visualizing changes in tissues or organs
Cytologic tests require the biopsy or cell sample
histologic and cytologic examinations to determine degree of differentiation and tumor type
may be tested for growth promoter sensitivities, eg: estrogen-dependent tumors
most dependable confirmation of malignancy
risk factors
genetic factors; radiation
chemicals (risk factors)
organic solvents asbestos heavy metals formaldehyde chemotherapy agents
biological factors of cancer
chronic irritation and inflammation
age
diet
hormones
risk reduction
limit UV exposure from sun or tanning booths
regular medical and dental exams
self-examination
diet (increased fiber content, reduced fats, 5-10 servings of fresh fruits and vegetable, these foods contain antioxidants which reduce changes to DNA)
immunity and cancer risk
- cell-mediated immunity recognizes some tumor cells and destroys these
- immunization for cervical cancer and hepatitis is recommended to reduce cancer risk from infection
cancer-free state generally defined when
as a 5-year survival without recurrence
-some cancers such as childhood leukemias can be considered cured after a 10 year cancer free period
remission
no clinical signs of cancer
-client may experience several remissions
examples of malignant tumors
skin cancer, ovarian cancer and brain tumor
