Surgical oncology Flashcards
What are the phenotypic characteristics of neoplasia?
- Self sufficiency in growth signals
- Insensitivity to anti-growth signals
- Tissue invasion and metastasis
- Limitless replicative potential
- Sustained angiogenesis
- Evasion of apoptosis
What can activate oncogenes?
Chromosomal translocation, gene amplification, point mutations and vital insertions
What are the stages of cell progression toward a malignant phenotype?
Initiation, promotion, progression
What are the only neoplasms with established heritability in dogs?
Osteosarcoma in scottish deerhounds, renal cystadenocarcinoma and nodular dermatofibrosis in German shepherds
What is an oncogene?
A mutated version of a normal gene that drives the formation of cancer
What are the main classes of proteins that translation of oncogenes lead to the transcription of?
Growth factors, growth factor receptors, cytoplasmic kinases/Ras, transcription factors, antiapoptotic proteins
What is the mechanism of action of Toceranib (Palladia)?
It is a tyrosine kinase inhibitor. This is used in dogs exhibiting mutation of the c-kit receptor which leads to a constitutively active c-kit receptor tyrosine kinase receptor and increased proliferative activity
What is the ‘two-hit hypothesis’?
For mutations in tumor suppression genes to occur both alleles need to be damaged
What are the two groups of tumour suppression genes?
Gatekeeper and caretaker
Mutations of what tumour suppression gene have been identified as a prognostic factor for osteosarcoma and canine mammary tumours?
p53 gatekeeper gene
Do canine neoplastic tissues express increased or decreased levels of telomerase activity?
Increased - potentially leading to increased replicative potential. Telomerase is responsible for adding sequences onto the end of telomeres which undergo shortening with each cellular replication (end replication problem)
What are the three major routes of metastasis?
Hematogenous, lymphatic, direct seeding
What is the most common route of carcinoma and round cell tumour metastasis?
Lymphatic
What is the most common route of sarcoma metastasis?
Hematogenous
What type of ultrasonography can be useful in differentiating between benign and malignant splenic neoplasms?
Enhanced harmonic ultrasound