Choose the most correct answer to complete this sentence.
A carcinoma is ____________________
A tumour of circulating blood cells
A benign tumour of glandular origin
An aggressive tumour of blood cell origin localised to the lymph nodes
A tumour of epithelial cell origin
An activating mutation of H-Ras proto-oncogene leads to self-sufficiency in growth signal. Which of the following reasons best explains the mechanism?
Cyclin D expression is decreased in the absence of mitogen
C-myc activity is increased in the absence of mitogen
A decrease in E2-F transcription factor activity is stimulated in the absence of a mitogen
An increase in hypophosphorylated pRB is stimulated in the absence of a mitogen
Why is p53 a critical tumour suppressor gene?
It is an essential component of the apoptotic pathway
It repairs DNA damage
It has key roles in cell cycle progression, apoptosis and maintenance of genetic stability
It is essential for normal development
The progression of breast cancer from primary lesion to metastatic disease is a multifactorial process. Which of the following statements is INCORRECT:
A cancer cell escapes its local environment by initially invading the basement membrane
An epithelial cell undergoes a process termed mesenchyme-to-epithelial transition during initial vessel invasion
Invasion of the lymph and blood vessels is an early step in tumour cell dissemination
Disseminated tumour cells can lie dormant for years before reinitiating a program of cell growth to colonise a distal site
Below is a population doubling vs time graph (time on the X axis and population doublings on the Y axis). If a cell culture is proliferating at point X, what would need to happen to the culture in order to continue proliferating to point Y?
The cell culture would continue to grow to point Y if a tumour suppressor mechanism was activated.
The cell population is immortal, so the cells will continue to grow past point Y indefinitely.
Cells would continue to proliferate to point Y if a tumour suppressor gene was inactivated.
The cells will enter crisis, a rare cell will escape crisis by activation of a telomere maintenance mechanism, and the culture will be immortal.
Our lab obtained an immortal cell line from a collaborator, and we don’t know whether the telomeres are being maintained by telomerase or the Alternative Lengthening of Telomeres (ALT) mechanism. We performed assays to determine the telomere maintenance mechanism and the results are listed below. Can we determine which method of telomere maintenance has been activated?