Flashcards in 9. Fundamentals of Neoplasia Deck (49):
Where does most of the neoplasias arise from?
From epithelium (90%). The remainder arise from mesenchymal cells.
What is carcinogenesis?
A multistep process involving a sequence of initiation (mutation) followed by promotion (proliferation).
What are initiators?
They are direct-acting chemical carcinogens. These are mutagens that cause cancer directly by modifying DNA.
What are promotors?
They cause cellular proliferation of mutated (initiated) cells. Proliferation of a mutated cell may lead to accumulation of additional mutations.
What do nitrosamines cause?
What do polycylic aromatic hydrocarbons cause?
What does asbestos cause?
Bronchogenic carcinoma, mesothelioma.
What does chromium and nickel cause?
What does arsenic cause?
Squamous cell carcinomas of skin and lung, angiosarcoma of liver.
What does vinyl chloride cause?
Angiosarcoma of liver.
What does aromatic amines and azo dyes cause?
What does alkalating agents cause?
Leukemia, lymphoma, other cancers.
What does benzene cause?
What does napthylamine cause?
What method employs bacteria to test potential carcinogens?
What is the effect of ultraviolet radiation on cells?
Produces pyrimidine dimers in DNA leading to transcriptional errors and mutations of onogenes and tumor suppressor geners.
What is Xeroderma Pimentosum?
Autosomal recessive inherited defect in DNA repair; they can't repair the pyrimidine dimers caused by UV light.
What is the effect of ionizing radiation on cells?
They cause cross-linking and chain breaks in nucleic acids.
What stage of cell cycle is most vulnerable to ionizing radiation?
Cells in mitosis or G2 of the cell cycle.
What are the sources of ionizing radiation?
X-rays, gamma rays, alpha and beta particles, protons and neutrons, atomic bombs and uranium miners.
Give an example of RNA oncogenic virus.
The human T-cell leukemia virus (HTLV-1) causes adult T-cell leukemia/lymphoma.
What are four DNA oncogenic virus?
I. Hepatitis B virus. II. Epstein-Barr virus (EBV). III. Human papilloma virus (HPV). IV. Kaposi-sarcoma-associated herpesvirus (HHV8).
What type of cancer does Hepatitis B virus cause?
What type of cancer does Epstein-Barr virus (EBV)?
I. Burkitt lymphoma. II. B-cell lymphomas in immunsuppressed patients. III. Nasopharyngeal carcinoma.
What type of cancer deos Human papilloma virus (HPV)?
I. Benign squamous papillomas (warts). II. Cervical cancer.
What does p53 tumor suppresor gene do?
Prevents a cell with damaged DNA from entering S-phase by promoting apoptosis in said cells by stimulating bax synthesis.
What does Rb tumor suppresor gene do?
Prevents the cell from entering S-phase unti the appropriate growth signals are present.
What is Knudson's "two hit hypothesis"?
Both tumor suppresor genes must be inactivated for oncogenesis.
What would be an example of a first hit in Knudson's hypothesis?
An inherited germ-line mutation.
What would be an example of a second hit in Knudson's hypothesis?
An acquired somatic mutation.
What are two examples of inherited germ-line mutation?
Familial retinoblastoma and Li-Fraumini syndrome.
What is Familial retinoblastoma?
Caused by Germ-line muation of Rb on chromosome 13, it causes high rate of retinoblastoma and osteosarcoma.
What is Li-Fraumini syndrome?
Caused by Germ-line muation of p53 on chromosome 17, it causes high rate of many types of tumors.
What does bcl-2 do?
Prevents apoptosis. It is overexpressed in follicular lymphomas t(14:18) = Chrom14 - immunoglobulin heavy chain gene and Chrom18 - bcl-2 gene.
Which four genes promote apoptosis?
bax, bad, bcl-xS, bid
What does c-myc do?
Promotes cellular proliferation.
What diseases are associated with alpha-fetoprotein (AFP)?
Hepatoma, nonseminomatous testicular germ-cell tumors.
What diseases are associated with beta human chorionic gonadotropin (hCG)?
Trophoblastic tumors, choriocarcinoma.
What diseases are associated with cacitonin?
Medullary carcinoma of the thyroid.
What diseases are associated with carcinoembryonic antigen (CEA)?
Carcinomas of the lung, pancreas, stomach, breast and colon.
What diseases are associated with alpha-fetoprotein CA-125?
What diseases are associated with CA19-9?
What diseases are associated with placental alkaline phosphatase?
What diseases are associated with PSA?
What diseases are associated with prostatic acid phosphatase?
What does TNM staging system criteria stand for?
T: Size of the primary tumor. N: Extent of regional lymph node spread. M: Presence of metastatic disease.
What is the most common rout of spread for epithelieal carcinomas?
Which carcinomas spread through the blood?
Most sarcomas, renal cell carcinoma, hepatocellular carcinomas, follicular carcinoma of the thyroid, choriocarcinoma.