Chapter 6: Neoplasia Flashcards
Anaplasia
loss of cell differentiation in cancerous tissue
Telomerase
enzyme released by cancer cells that continually replaces telomeres allowing cells to replicate indefinitely
Cancer cells are AUTONOMOUS
divide without receiving chemical signals from the body
Cancer Characteristics
lack cell density (dependent or contact inhibition) anchorage independent mutations of genes oncogenes angiogenesis metastasis
Dependent or Contact Inhibition
most healthy cells stop dividing if their environment becomes too crowded
cancer cells continue to grow
Anchorage Independent
malignant cells do not have to be anchored to other cells or a surface - can shed their surface cells
Point mutation
a single change in a nucleotide
DNA amplification
repeated copying of a sequence of DNA
Chromosomal Rearrangement
chromosome is attached to an area where it should not be
Epigenetic Modification
may silence genes (such as tumor suppressor gene) so that even though the gene is present, it is not expressed
Proto-oncogenes
genes that are responsible for making cells divide
they code for normal cell division proteins
Oncogenes
gene associated with initiation of mutated changes
pro-mitotic and proliferative
Tumor Suppressor Cells
inhibits cell division and triggers apoptosis
Angiogenesis
growing tumors send out signals that say “Feed me”
blood vessels send over new extensions for O2 and food
also serve as passageway for metastasis
Metastasis
cancer cells break off from the original (primary) tumor) and move through the body to form new tumors elsewhere
Characteristics of BENIGN Tumors
loss of the ability to control cell proliferation
slow growing
well-differentiated cells (may perform normal function)
encapsulated
noninvasive
Characteristics of MALIGNANT Tumors
loss of the ability to control both proliferation and differentiation
grow rapidly
poor differentiation
not encapsulated - send out legs
infiltrate/invade, metastasize
may secrete own GFs, enzymes, toxins, etc.
Cancer In Situ
localized and pre-invasive
cancer has not crossed the basement membrane
Types of Malignant Neoplasms: Solid
initially confined to a specific tissue/organ but eventually invades and breaks through the basement membrane
may spread via the blood or lymph system
Types of Malignant Neoplasms: Hematologic
involves cells normally found in blood or lymph, disseminated from the beginning
Example: leukemia
Carcinogenesis
the process by which carcinogenic agents cause normal cells to become cancer cells
occurs in stages: initiation, promotion, and progression
Initiation
Carcinogenesis
exposure to carcinogenic agents
proto-oncogenes are activated and tumor suppressor genes are inactivated
Promotion
Carcinogenesis
mutated cells are stimulated to divide = unregulated accelerated growth
Progression
Carcinogenesis
tumor cells acquire malignant phenotypic changes
develop more mutation (become more aggressive)
Causative Factors of Cancer:
Heredity
inheritance of defective genes involved with cell proliferation or apoptosis
Example: BRCA
Causative Factors of Cancer:
Reproductive Hormones
hormones often trigger cell growth and division and can promote cancerous cell division
Example: a tumor may be estrogen sensitive
Causative Factors of Cancer:
Obesity
overproduction of insulin and IGF stimulates proliferation and inhibits apoptosis
Causative Factors of Cancer:
Immune surveillance and tumor antigens
process can be inhibited by immunodeficiency
cell can change expression of proteins to be recognized as “self” so they are not killed
Causative Factors of Cancer:
Chemical Carcinogens
nicotine, alcohol, high-fat diet
damage DNA, RNA, or proteins involved in the control of cell proliferation
Causative Factors of Cancer:
Radiation
causes direct changes to DNA resulting in gene or chromosomal changes
Causative Factors of Cancer:
Viruses/Bacteria
pathogens may stimulate cell changes
Examples: HPV, EBV, Hep B and C, H. pylori
Causative Factors of Cancer:
Chronic inflammation
stimulates cell proliferation and blood vessel growth
releases oxygen-reactive species that promote mutations
Clinical Manifestations of Cancer
loss of tissue integrity anemia cachexia fatigue paraneoplastic disorder
Cachexia
weight loss and wasting of body fat and muscle tissue due to hypermetabolic state of cancer
Paraneoplastic Disorder
may be earliest indication a person has cancer
range of effects at sites not directly associated with the tumor d/t release of hormones/hormone-like proteins from cancer cells
Examples of Paraneoplastic Disorders
SIADH - release of ADH by tumor
Cushing’s - release of ACTH by tumor
Hypercalcemia - release of PTH-related protein
DVT d/t production of procoagulation factors
Grading
microscopic exam of differentiation
1 = well-differentiated
4 = poorly differentiated
Staging (TNM)
T = Tumor size N = lymph Node involvement M = Metastasis
