L8 Neoplasia III Flashcards
Tumors begin as monoclonal; what happens next?
Sub-clones arise from the descendants of the original transformed cell by multiple mutations; these cells have specific evasive functions.
___ agents inflict genetic damage.
Carcinogenic
What are three types of carcinogenic agents?
- Chemicals
- Radiant energy
- Microbial agents
What is the difference between direct acting and indirect acting chemical carcinogens?
Direct acting require no metabolic conversion; indirect acting require metabolic conversion
Carcinogenicity may be augmented by promoters - what are these?
Non-tumorigenic compounds which facilitate the induction of cell proliferation in the initiation-promotion sequence
Given the toxin, name the organ affected and the resultant cancer: vinyl chloride
Liver; angiosarcoma
Given the toxin, name the organ affected and the resultant cancer: nitrosamine (smoked foods)
Stomach; gastric cancer
Given the toxin, name the organ affected and the resultant cancer: asbestos
Lung; mesothelioma, bronchogenic carcinoma
Given the toxin, name the organ affected and the resultant cancer: arsenic
Skin; squamous cell carcinoma
Given the toxin, name the organ affected and the resultant cancer: napthalene (analine) dyes
Bladder; urothelial carcinoma
Given the toxin, name the organ affected and the resultant cancer: aflatoxin B
Liver; hepatocellular carcinoma
What are some sources of radiation carcinogenesis?
- Sunlight (UV)
- X-rays
- Nuclear fusion/ionizing radiation
- Fission by-products
- Radionucleotides
How does ionizing radiation act as a carcinogen?
Chromosome breakage, translocations, point mutations, all leading to genetic damage
What type of cancer is associated with ionizing radiation?
Papillary carcinoma of the thyroid
How does UV light act as a carcinogen?
Damages DNA by forming pyrimidine dimers
What type of cancer is associated with UV light?
Skin, squamous cell, basal cell, and melanoma
True or false - radiation initiation is reversible due to its long latent period.
False - it is irreversible despite a long latent period
What is the defect in xeroderma pigmentosum?
Defect in nucleotide excision repair pathway; increased disposition to skin cancer
What is a type of RNA virus that can cause cancer, and what type?
Human T-cell lymphotropic virus (HTLV-1) –> T cell leukemia/lymphoma
What are 3 types of DNA viruses that can cause cancer, and what type?
- HPV –> benign warts, cervical cancer
- Epstein Barr Virus (EBV) –> Burkitt lymphoma, nasopharyngeal carcinoma
- Hepatitis B/C –> hepatocellualr carcinoma
What is a type of bacteria that can cause cancer, and what type?
Helicobacter pylori –> gastric adenocarcinoma, MALT lymphoma
What are the 4 major anti-tumor effector mechanisms?
- Cytotoxic T lymphocytes
- NK cells
- Macrophages
- Humoral mechanisms
___ patients are at an increased risk for cancer development.
Immunosuppressed
What are several ways cancers can evade the immune system?
- Eliminate strongly immunogenic sub-clones.
- Fail to express HLA class I, escape cytotoxic attack
- Suppress host immune response by secreting TGF-beta, expressing FasL, and activating tRegs.
What are some effects of the tumor on the host?
- Compress structures
- Ulcerate through surfaces
- Affect hormone production
- Cancer cachexia
What are symptom complexes that cannot be readily explained by local or distance spread?
Paraneoplastic syndromes
What is grading of a tumor?
An attempt to estimate the aggressiveness of the tumor based on cytologic differentiation
What 4 aspects are considered when grading a tumor?
- Degree of cellular differentiation
- Degree of cellular pleomorphism
- Degree of loss of normal architecture
- Mitotic index
How are tumors staged according to size?
CIS (carcinoma in situ) - confined to epithelium T1 - through basement membrane T2 - into muscle T3 - into fat T4 - out of tissue
How are tumors staged according to the extent of spread to lymph nodes?
N0
N1
N2
N3
How are tumors staged according to metastasis?
M0 - none
M1 - metastasis
Which is of greater clinical value - staging or grading?
Staging
What are two major tumor associated markers?
- Alpha-fetoprotein (AFP)
2. Carcinoembryonic antigen (CEA)
What cancers are associated with AFP?
Liver carcinomas, tumor of yolk sac remnants, gonadal tumors
What cancers are associated with CEA?
Colon, pancreas, lung, stomach, breast
Tumor associated markers are most useful for what?
Detecting recurrence of disease