TVT Flashcards
(18 cards)
How is TVT transmitted - vertical or horizontal
Horizontal via coitus
Who is at greatest risk for TVT
Free roaming sexually intact mature dogs
What ages is TVT most common in
2-5y
What are the only known naturally occurring clonally transmissible cancers that behave like an infectious parasitic neoplastic tissue graft
TVT
Tasmanian devil facial tumor disease
Also clams maybe?? Clonally transmissible, doesn’t need contact
Maybe hamsters (not sexually transmitted though)
NOT sea lions
Met rate for TVT
5-17%
IHC for TVT
Vimentin +
Lysozyme +
Alpha-1-antitrypsin (AAT) +
Macrophage-specific ACM1 +
P53+ +
PCNA +
Ki67 +
MYC +
Rb +
Cyclin D1 +
MMP-2 and MMP-9 +
S-100 variable
Insertion of what upstream of c-myc is found in TVT
LINE-1
**Can use LINE-c-MYC gene sequence with PCR to diagnose TVT
Point mutations in what tumor suppressor gene have been identified in TVT
p53
Growth phases of TVT
Progressive phase (P) - tumor grows for 3-6m
Stationary phase (S) - can last for months to years
Regressive phase (R) - doesn’t happen in elderly dogs, dogs in poor general condition, or immunologically compromised dogs
What is downregulated in the P have of TVT growth
MHC class I beta2-microglobulin and MHC class II —> allows immune evasion of host histocompatibility barrier, especially T-cell cytotoxicity
TVT secretes what to inhibit tumor MHC antigen expression and NK cell activity
TGF-1beta
What happens late in the P phase to synergize with IFN-gamma and antagonize immunoinhibitory effect of TGF-beta1
Increase in immune cell infirlatraion occurs and TILs produce high concentrations of IL-6
Are puppies born to mothers that had TVT more or less susceptible to disease
LESS - mom has serum transferable immunity to reinfection that can be transferred to the puppies
On cyto of a suspect TVT you see a large number of lymphocytes infiltrating the tumor. What does this tell you?
It is in the R phase
Regressing tumors are infiltrated by lymphocytes, plasma cells, and macrophages
Response rate of TVT to single agent vinc
90-95%
What drug can be used for resistant cases
Doxorubicin
Is TVT RT responsive?
Yes - 18 of 18 dogs responded to orthovoltage RT - CRs and durable, 7 only needed one fraction
Recurrence rate with sx for TVT
30-75%
