Pathoma Chapter 3A Flashcards
Neoplasia is
new tissue growth that is unregulated, irreversible, and monoclonal
What features distinguish neoplasia from hyperplasia and repair?
unregulated, irreversible, and monoclonal
Monoclonal means
that the neoplastic cells are derived from a single mother cell
Clonality can be determined by?
glucose-6-phosphate dehydrogenase (G6PD) enzyme isoforms.
Multiple isoforms
G6PDA, G6PDb, and G6PDc exist; only one isoform is inherited from each parent.
lyonization
In females, one isoform is randomly inactivated in each cell by lyonization
G6PD is present on what chromosome
X
Normal ratio of active isoforms in cells of any tissue is
1:1 (e.g 50% of cells have G6PDa , and 50% ofcells have G6PDG)
In hyperplasia what happens to the ratio?
1:1 ratio is maintained in hyperplasia, which is polyclonal (cells are derived from multiple cells).
In neoplasia what can be said about the isoform?
Only one isoform is present in neoplasia, which is monoclonal
Clonality can also be determined by
androgen receptor isoforms, which are also present on the X chromosome.
Clonality of B lymphocytes is determined by
immunoglobulin (Ig) light chain phenotype.
Ig is comprised of
heavy and light chains.
Each B cell expresses
light chain that is either kappa or lambda.
Normal kappa to lambda light chain ratio is
3:01
Kappa to lambda ratio in hyperplasia
This ratio is maintained in hyperplasia, which is polyclonal
kappa to lambda ratio in lymphoma?
Ratio increases to > 6:1 or is inverted (kappa to lambda ratio = 1:3) in lymphoma, which is monoclonal
Neoplastic tumors are
benign or malignant
Benign tumors
remain localized and do not metastasize
Malignant tumors
(cancer) invade locally and have the potential to metastasize.
Tumor nomenclature is based on
lineage of differentiation (type of tissue produced) and whether the tumor is benign or malignant
What benign growths result from the epithelium?
Adenoma, papilloma
What malignant growths result from the epithelium?
Adenocarcinoma and papillary carcinoma
What benign growths result from the mesenchyme?
Lipoma
What malignant growths result from the mesenchyme?
Liposarcoma
What benign growths result from the lymphocyte?
Does not exist
What malignant growths result from the lymphocyte?
Lymphoma/Leukemia
What benign growths result from the melanocyte?
Nevus (mole)
What malignant growths result from the melanocyte?
Melanoma
What is the 2nd leading cause of death in both adults and children?
cancer
What are the leading causes of death in adults?
(1) cardiovascular disease (2) cancer (3) cerebrovascular disease
What are the leading causes of death in children?
(1) accidents (2) cancer (3) congenital defects
What are the most common cancers by incidence in adults?
(1) breast/prostate (2) lung (3) colorectal.
What are the most common causes of cancer mortality in adults?
(1) lung (2) breast/prostate (3) colorectal
Cancer begins as a
single mutated cell.
Approximately how many divisions occur before the earliest clinical symptoms arise?
30
Cancers that do not produce symptoms until late in disease
will have undergone additional divisions and, hence, additional mutations.
Cancers that are detected late
tend to have a poor prognosis.
Goal of screening is
to catch dysplasia (precancerous change) before it becomes carcinoma or carcinoma before clinical symptoms arise.
Common screening methods include
- Pap smear 2. Mammography 3. PSA and DRE 4. Hemoccult test and colonoscopy
Pap smear
detects cervical dysplasia (CIN) before it becomes carcinoma
Mammography
detects in situ breast cancer (e.g DCIS) before it invades or invasive carcinoma before it becomes clinically palpable
PSA and DRE
Prostate specific antigen (PSA) and digital rectal exam detects prostate carcinoma before it spreads
Hemoccult test
for occult blood in stool
colonoscopy
detect colonic adenoma before it becomes colonic carcinoma or carcinoma before it spreads
Cancer formation is initiated by
damage to DNA of stem cells. The damage overcomes DNA repair mechanisms, but is not lethal.
Carcinogens are
agents that damage DNA, increasing the risk for cancer.
Important carcinogens include
chemicals, oncogenic viruses, and radical ions
DNA mutations eventually disrupt
key regulatory systems, allowing for tumor promotion (growth) and progression (spread)
Disrupted key regulatory systems include
proto-oncogenes, tumor suppressor genes, and regulators of apoptosis
