Oefentoets Flashcards
What is the name of a benign tumor originated from cartilage called?
Chondroma
A patient tumor is grading reports states ‘‘Well differentiated, grade 1’’. What does this mean?
Tumor cells have an appearance and arranged that is similar to normal cells –> benign
1 theory that is used to explain the formation of metastasis is the ‘‘Seed and Soil’’ theory. What is meant by the Soil?
The secundary organ in which the metastasis forms
The sectreted Soluble factors is 1 caterogy comprimising the components of the tumor microenvironment. Which statement is NOT correct regarding this caterogy? Pick 1
- They are NOT involved in Angiogenesis
- They ARE involved in Matrix remodelling
- Proteases are part of this category
- Cytokines and chemokines are part of this category
They are NOT involved in angiogenesis is wrong
Which of the following are hallmarks of cancer?
- Sustaining proliferative signaling
- Avoiding immune destruction
- Enabling replicative immortality
All of them are part of the hallmarks of cancer
What is called the ‘‘Gatekeeper’’ to colorectal cancer development?
APC/Wnt signaling pathway
What can be present on MHCII in Dendritic Cells?
Only peptides from EXTRAcellular matrix
What is NOT a mechanism by which tumor cells can evade the IS?
- Poor immunogenicity
- Tolerance of the tumor Ag
- Down-regulation of MHCII
- Recruitment/stimulation of Treg
Down-regulation of MHCII
In dendritic cell therapy for cancer patients, APC’s (monocytes ex.) are taken out of the circulation of a patient, differentiated to dendritic cells, loaded with Ag ex vivo and injected back into the patient. What is the advantage of this kind of therapy for cancer patiens?
It can induce memory
Which of the following protein is defined as a signaling protein?
- Frizzled
- Sonic Hedehog SHH
- Beta catenin
- Oct4
SHH
After EMT, which of these characteristics is not shown?
- Loss of cell polarity
- Migration features
- Acquidition of cell adhesion
- Loss of cell adhesion
Acquisition of cell adhesion
In a Wildtype, NOT transgenic mouse, which is a gene specifically expressed in an intestinal adult stemcell
- Oct4
-Wnt 3A - GFP
- Lgr5
Lgr5
Which of the DNA repair mechanism uses sequences in the undamaged sister chromatid?
-BER
-HR
-MMR
-NER
HR
Benign tumors usually donot have fatal outcome. Give an example in which a benign tumor COULD have a fatal outcome and why it can be fatal
- Anatomical position: Benign tumor pushing against brain tissue
- Systemic effect: Adenoma: insulin producing pancreatic cancer
Why is angiogenesis so important in cancer progression?
New bloodvessels help the tumor to grow by feeding the cancer cells with nutrients, oxygen AND it helps by metastase
Explain at molecular level how an APC mutation contributes to colorectal cancer
APC is involved in the Wnt signaling cascade. When APC is mutated, it cannot bind beta-catenin and therefore beta-catenin is not in the complex anymore with APC, axin, GSK3 and CK1. So beta-catenin will not be phosphorylated and degraded. It is now present and stable form without the Wnt signal. Stable beta-catenin binds to the transcription factors bound to the DNA (LEF1/TCF). This will lead to uncontrolled transcription of Wnt target genes. Ongoing Wnt signaling because of mutated APC causes more proliferation than differentiation, this imbalance can cause colorectal cancer
Name a mechanism how NK-cells can kill a tumor cell
- Intrinsic mechanism: Perforin-granzyme
- Extrinsic mechanism: TNF/TNFR
Explain what is meant by ‘‘escape’’ in the immune surveillance hypothesis
The IS can no longer kill all carcinogenic cells, causing them to grow into a tumor
Name a disadvantage of using Ab’s as tumor immunotherapy
Does not provide memory, not patient specific
In different tumor types, the mutation of APC causes overactivation of the Wnt signaling pathway. How does the loss of APC activate Wnt signaling?
APC is part of the beta-catenin digradation complex. Without APC, beta-catenin is not degraded and is continously going to the nucleus
What kind of function do tumor suppressor proteins have
They have apoptotic and/or anti-proliferative functions to counterbalance proliferative signals, especially in case of oncogenic stimuli
How are phosphotyrosine docking sites for STATS created
2 JAKS phosphorylate each other. This increases the activity of the tyrosine kinase domains of the JAKS. Then the JAKS can phosphorylate tyrosines on the cytoplasmic tails of the cytokine receptors. This creates phosphotyrosine docking sites for STATS
What is the function of Ksr in the RAS-MAPK signaling pathway
Ksr is an important scaffold protein that contains bindngsites for Rad, Mek and Erf. The scaffold protein helps with the transduction of signals and organisation of Rad, Mek and Erf
Which kind of stem cells are the cells within the inner cell mass
Embryonic stem cells (pluripotent stem cells). This is because each of them can give rise to all the cell types in the body
Describe what happens in G1 –> S arrect following DNA damage
DNA damage causing activation of protein kinases (ATM/ATR and Chk1/Chk2) that phosphorylates P53, the phosphorylated P53 has now a lower affinity binding to Mdm2. Arf will help removing Mdm2 and now there is a stable P53. Stable and active P53 can bind to the regulatory region of P21 gene as a transcription factor, producing P21 (Cdk inhibitory protein). P21 suppresses G1/S Cdks and S Cdk activities by binding to the Cyclin-Cdk complex
What is a Pyrimidine dimer
Covalent cross-links between adjacent pyrimidine bases in DNA
Why do transplantation patients have a higher risk of developing tumors?
They take immunosuppressiva which block the adaptive IS
Testis Ag’s are a type of tumor Ag
True
Which cells can cross present Ag’s
Dendritic cells
How many signals does a cytotoxic Tcell need to kill a TARGET CELL, and what is the signal
1 signal from the MHCI peptide
To which cells do tumors become vulnerable after downregulating MHCI
NK cells. They will still kill them. Tumors will be invivable for cytotoxic Tcells
What is a neo-epitode
Newly immunogenetic version of protein evoking Tcell response
