Cancer (Exam 4) Flashcards
Term for healthy cells transforming to cancer cells (forming neoplasms).
Oncogenesis
Oncogenesis is a combination of ______ and _______ changes.
cellular & genetic
Abnormal tissue mass with uncoordinated and unregulated growth.
neoplasm/tumor
All malignant neoplasms (gain ability to invade/metastasize) are commonly called:
cancer
Term for change in cell growth properties after viral infection.
transformation
Process for when the viral genome persists in tumor cells and viral genes expressed promote autogenous growth and neoplastic cell survival:
viral oncogenesis
Transfer of genes from virus to host:
transduction
List the 4 gene targets of genetic damage (which can be related to formation of cancer).
- proto-oncogenes
- tumor suppressor genes
- apoptosis-regulating genes
- DNA repair genes
Match the gene which is a target for genetic damage to its typical function:
- inhibit cell growth
- regulate cell-growth & proliferation
- inhibit damaged DNA cell division
- initiate cell death
- tumor suppressor genes
- proto-oncogenes
- DNA repair genes
- apoptosis-regulating genes
(T/F) Genes targeted for damage can contribute to cancer development BEFORE viral infection as the “second hit”.
False - virus is “first hit” and mutation after
Viral carcinogenesis uses _______ and ______ molecular changes to cause neoplasia.
direct and indirect
Direct mechanisms for viral carcinogenesis include formation of oncogenes, blocking of apoptosis, and activating telomerase. What are 2 indirect mechanisms?
- chronic inflammation
- immunosuppression
Immunosuppression causes viral carcinogenesis indirectly by causing hyperplasia –> dysplasia –> neoplasia.
False - chronic inflammation
Immunosuppression indirectly contributes to viral carcinogenesis by disables _______ cells.
CD8+ cytotoxic T cells
Which group of RNA viruses are oncogenic?
retroviruses
Retroviruses are a group of oncogenic RNA viruses which all have which enzyme?
Reverse transcriptase (RNA –> DNA)
Retroviruses are (ss/ds) (DNA/RNA), (enveloped/nonenveloped) viruses.
ssRNA enveloped
(T/F) Retroviruses are cytolytic.
False (NOT cytolytic)
List the 3 mechanisms Retroviruses use for development of cancer.
- transduction
- insertional mutagenesis
- alter cell function (v-onc)
Retroviruses use transduction for development of cancer by inserting ______ into the host cell genome.
v-onc
(T/F) 100% of Retrovirus infection leads to transformation / tumor development.
True
During insertional mutagenesis used by retroviruses, ________ is inserted which causes cell growth.
provirus
Term for the viral nucleic acid sequence inserted in Insertional Mutagenesis.
provirus
Retroviruses use insertional mutagenesis which have a ________ period.
latency (low transformation rate)
_______ alters cell function with a long latency period but NO transduction. Less than 5% infected hosts will develop tumors.
v-onc
List the 3 retroviruses discussed which cause Viral Oncogenesis.
- Feline Leukemia Virus
- Bovine Leukemia Virus
- Avian Leukosis & Sarcoma Viruses
In addition to retroviruses, _________ can cause oncogenesis leading to Marek’s Disease in chickens.
Gallid Herpesvirus-2
Feline Leukemia Virus is a (core/non-core) vaccine for kittens and a (core/non-core) vaccine for adults.
Kittens: core
Adults: non-core
List the 4 subtypes of FeLV. Which is the infectious type?
FeLV-A *infectious
FeLV-B
FeLV-C
FeLV-T
(T/F) FeLV-B, C, and T are all mutated and recombinant forms of FeLV-A once in an infected cat.
True
________ ________ virus is a recombination of FeLV-A with a cell gene which leads to an oncogene.
Feline Sarcoma virus
(T/F) FeLV can be transmitted horizontally and vertically.
True
Which 2 ways can FeLV be transmitted horizontally? Which is more significant and prolonged?
- saliva (prolonged)
- fomites (do not persist)
List the 3 ways FeLV can be transmitted vertically.
- transplacental
- milk
- queen saliva
After oronasal exposure, FeLV replicates in ________ & _______, leading to a primary viremia and subsequent __________ infection.
lymphocytes & macrophages
bone marrow
Once FeLV infects the bone marrow precursor cells, it infects ________ and infects target organs such as thymus, spleen, salivary gland, mammary gland, and mucosal epithelium.
leukocytes/platelets
(T/F) FeLV can be shed in saliva, nasal secretions, milk, and feces.
True
List the 4 possible outcomes of FeLV exposure.
- no infection
- abortive infection
- latent infection
- progressive infection
Only cats with a _______ FeLV infection are infectious and are likely to develop clinical disease in the future.
progressive
Match the FeLV exposure outcome to their test results:
- Positive antibody & PCR
- ALL positive tests
- ALL negative tests
- All negative except p27 antigen test
- latent infection
- progressive infection
- no infection
- abortive infection
List the 3 genes FeLV uses to directly cause oncogenesis via insertional mutagenesis.
- gag gene
- env gene
- pol gene
Gag gene, used in FeLV insertional mutagenesis, encodes _______, a core protein, often used as an antigen for diagnostic tests.
p27
In FeLV insertional mutagenesis, Env gene uses ______ and ______ to modulate the host’s immune response.
gp70 + p15E
In FeLV insertional mutagenesis, the pol gene is used to encode:
reverse transcriptase
What indirect mechanism does FeLV use to cause cancer?
immunosuppression
List 3 methods of FeLV testing.
- blood (ELISA & RIM)
- IFA (immunofluorescent antibody)
- PCR
FeLV blood tests such as ELISA & RIM and IFA detect _______ to diagnose disease.
p27
Regarding FeLV testing, PCR detects ________ DNA and RT-PCR detects FeLV _______.
provirus
RNA (virions)
What are the 4 major disease syndromes that occur from FeLV infection?
- neoplasia
- immunosuppression
- non-neoplastic disorders
- reproduction failure
List 3 types of neoplasia that develop due to FeLV in cats.
Lymphosarcoma
Leukemias
Fibrosarcomas (FeSV)
Immunosuppression due to FeLV can cause a Type ______ Hypersensitivity, or immune complex disease.
III
Non-neoplastic signs that can occur from FeLV infection are:
pancytopenia, anemia
Bovine Leukemia Virus causes what disease?
Enzootic Bovine Leukosis
Bovine Leukemia Virus uses insertional mutagenesis by inserting a provirus into which cells?
B cells
In addition to insertional mutagenesis, Bovine Leukemia Virus encodes _______ _______ as an oncogenic mechanism.
Tax protein
BLV encodes Tax protein which promotes ________ mitosis, inhibits ______, and decreases ________.
B cell
P53 (DNA repair gene)
IFN
Bovine Leukemia Virus establishes latency in:
B cells (IgM positive)
(T/F) Disease due to BLV is only seen in young cattle.
False - old (LONG latency)
Bovine Leukemia Virus is a _______ retrovirus and highly _______-associated.
delta
cell
Cattle have resistance to BLV by Class II MHC genes, ______, and an antibody response with specific virus-induced surface antigens, ______ and ______.
BoLA (bovine leukocyte antigen)
gp51 + p24
List 3 routes of BLV transmission.
- AI / repro exam
- blood transfer (needles, dehorn, flies)
- vertical transmission (milk, placental)
Which mode of BLV transmission is common?
vertical transmission
There are 4 possible outcomes from Bovine Leukemia infection. One outcome is NO infection. The other 3 outcomes are PERMANENT infections with a variety of sequelae. List the 3 possible sequelae in combination with permanent infection.
Permanent infection with:
1. NO disease
2. lymphocytosis
3. lymphosarcoma
3 stages of Bovine Leukemia Virus disease:
- asymptomatic stage
- persistent lymphocytosis
- lymphosarcoma
The lymphosarcoma stage of BLV disease requires ___________ _________ by the host cell.
malignant transformation
Enlarged lymph nodes and enteric, cardiac, or vertebral signs indicate which stage of BLV disease?
lymphosarcoma
_______ test is the official regulatory test for Bovine Leukemia Virus which is a (serology/PCR) test.
AGID
serology
AGID test is a serology test to diagnose BLV which stands for:
agar gel immunodiffusion assay
Marek’s Disease is caused by:
Gallid Herpesvirus-2
Gallid Herpesvirus-2 is a(n) _______ herpesvirus.
alpha
There are 3 serotypes of Gallid Herpesvirus-2 (Type 1, 2, 3) which cause Marek’s Disease. Which are oncogenic or non-oncogenic?
Type 1: oncogenic
Type 2: non-oncogenic
Type 3: non-oncogenic
Type 1 Gallid Herpesvirus-2 is oncogenic in what species?
chickens
Gallid Herpesvirus-2 (Marek’s Disease) causes latency in:
T cells
Gallid Herpesvirus-2 uses 3 oncogenic mechanisms. In addition to insertional mutagenesis, it encodes ______ protein and _________ complex.
Meq protein
telomerase
Meq protein blocks ________ and increases cell survival and motility.
apoptosis
Where is the virus shed in Marek’s Disease?
dander (feather follicles)
(T/F) Chickens infected with Gallid Herpesvirus-2 are lifelong carriers.
True
Chickens can have genetic resistance to Gallid Herpesvirus-2 by _________ on RBCs.
B21 alloantigen
Gallid Herpesvirus-2 infects chickens via inhalation and infects which cell type initially?
alveolar macrophages
After infecting alveolar macrophages, Gallid Herpesvirus-2 go to the spleen, thymus, and bursa and infect ______ cells.
B cells
After B cells are infected, a provirus is integrated and a latent infection occurs in ______ cells.
CD4+ T cells
Match the clinical syndrome caused by Marek’s Disease to its signs:
- paralysis of one or both legs/wings
- depression, ataxia, paralysis
- lymphocytes in irish
- feather follicle nodules
- neurolymphomatosis
- acute marek’s disease
- ocular lymphomatosis
- cutaneous marek’s disease
What is the major clinical sign of Marek’s Disease?
paralysis w/ leg extension
(T/F) Serology is commonly used to diagnose Marek’s Disease.
False (not helpful)
Avian Leukosis and Sarcoma Viruses are ______ retroviruses.
alpha
Two major groups of Avian Leukosis & Sarcoma viruses:
Endogenous
Exogenous
3 Oncogenic Mechanisms used by Avian Leukosis & Sarcoma Viruses.
- insertional mutagenesis
- lymphoid leukosis
- osteopetrosis
Term for below disorder caused by Avian Leukosis & Sarcoma Viruses:
Abnormal bone causing defective osteoclast resorption and enlargement/calcification of long bones, obliterating the marrow cavity
Osteopetrosis
Lymphoid leukosis due to Avian Leukosis & Sarcoma Viruses affects (male/female) chickens, causing nodular tumors in spleen, liver, and bursa.
female
Osteopetrosis affects (male/female) chickens.
male
Avian Leukosis & Sarcoma Viruses can be transmitted horizontally via direct contact and vertically via _________ which is a major source of infection.
egg albumin
Anemia, unthrifty, diarrhea, and distended abdomen are all signs of which oncogenic virus?
Avian Leukosis & Sarcoma viruses
Which virus is an avian retrovirus that causes fibrosarcomas and histiocytomas in young chicks, causing lethal infections?
Rous Sarcoma Virus