neoplasia Flashcards
what type of neoplasia has an increased mitotic index
malignant
define neoplasia
abnormal (excessive) cell growth and differentiation
define neoplasm
an abnormal mass (tumor)
can be malignant or benign
characteristics of malignant neoplasms
- undifferentiated cells (anaplasia)
- rapid, variable growth rate
- growth by invasion, infiltration of surrounding tissue
- metastasis
characteristics of benign neoplasms
- well-differentiated
- slower growth rate, may stop or regress
- growth by expansion (doesn’t invade)
- usually encapsulated
- does not metastasize
genes code for what
proteins, which have a function and do tasks
DNA repair genes
- “spell check” genes
- continuously read genetic code looking for errors (insertion/deletion/substitution) and deletes mistake
- fixes the problem now instead of removing the cell later
why do carcinogens target DNA repair genes
allows mutations to pass through
what are the cancer associated genes
- proto-oncogenes (go)
- tumor suppressor genes (stop)
proto-oncogenes
- go genes = promote cell growth
- mutation = excessive cell growth = tumors
tumor suppressor genes
- stop genes = inhibit cell growth
- mutation = excessive cell growth = tumors
- ex. TP53
what are oncogenes
any mutated cancer associated gene
suffix for a benign tumor
oma
suffix’s for malignant tumors
carcinoma
sarcoma
carcinoma refers to
arising from the epithelial tissue
sarcoma refers to
arising from mesenchyme origins (non-epithelial)
mesenchyme = embryonic tissue (present only in embryo)
how long does it take for a tumor to double
120 days (4 months)
how long does it take for a tumor to be clinically detectable
10 years
= 30 doublings, 1 cm in size, 1 billion cells
the size of a tumor is directly related to what
the number of cells
what does the TP53 gene code for
apoptosis of cells with DNA damage
50% of cancers have what mutated gene and what does it cause
TP53
increased survival of DNA damaged cells
methods of tumor spreading
- local = invasion of surrounding tissue
- seeding = distant spread within body cavities
- metastasis = distant spread through blood/lymph
what is a primary site?
where the tumor first formed
what is a secondary site? most common secondary site?
where the CA cells spread to and proliferate lymphatic tissue (lymph nodes)
sentinel lymph node
first lymph node affected by cancerous cells
after the secondary site, where do malignant cells usually travel to
liver, lungs, bones, brain
stage 1 of metastasis
- cells invade local tissue aided by enzymes that break up cementing material between cells
- malignant cells enter blood/lymph (emboli)
- 1/1000 cells survive defenses (blood turbulance makes it easier by dislodging them), survival aided by platelets that cover/protect them
stage 2 of metastasis
- cells travel until they reach an area of resistance (capillary beds)
- mediators (cytokines) scout and determine suitability of secondary site
- cells attach and proliferate (aided by cytokines and growth factor)
what determines suitability of a secondary site
- resources for growth and division
- protection from defenses
- room to grow
stage 3 of metastasis
- cell proliferation and angiogenesis
- requires resources (nutrients, energy, waste removal)
grading of tumors
I to IV
I = restrictive growth, IV = extensive growth
subjective, based on histology
higher grade = more anaplasia (worse outcome)
staging of tumors
TNM
T: 0-4 (size/measurement)
N: 0-3 (degree of lymph node involvement)
M: 0-1 (metastasis - spread to secondary site)
objective, clinical approach, global system
T1N0M0
small tumor, no lymph node involvement, no metastasis
T4N3M1
large tumor, many lymph nodes involved, metastases
treatment of cancer
- surgery
- radiation
- chemotherapy
- immunotherapy
- hormone therapy
- combination therapy
when can a tumor be surgically removed
- it must be restricted in growth and well defined
- not effective for advanced malignancy (multiple sites)
- direct, least SE
why is radiation used for tumor treatment
- tumor cells proliferate uncontrollably, radiation prevents this by creating free radicals that destroy cells and disrupt/prevent DNA replication
- problem: also kills and prevents division of normal cells
what does chemotherapy target
cell proliferation - rapidly growing cells
DNA, RNA, enzymes and protein synthesis
what does immunotherapy do
- stimulates the immune system to target malignant cells
- CA cell destruction via cytokines, Ab, Ag
- ex. provide Ag that resembles malignant cells
what does hormone therapy do
- disrupts hormonal supply that feeds the tumor
- disrupts cell fx
what is combination therapy used for
advanced disease or difficult to cure CA
problems with cancer treatment
- pressing side effects
- hard to restrict malignant cells
- normal rapidly proliferating cells also targetted
- recurrence of growth, despite previous cure
