PLEASE ANSWER ALL 4 QUESTIONS. PROMISE YOULL GET THREE THUMBS UP ;) 1. The rapid
ID: 204585 • Letter: P
Question
PLEASE ANSWER ALL 4 QUESTIONS. PROMISE YOULL GET THREE THUMBS UP ;)
1. The rapid-aging disorder Hutchinson-Gilford progeria syndrome results from an abnormal protein that causes the nuclear membrane to protrude inward, where it contacts the tips of chromosomes, perhaps shortening them. From this information, would you expect cancer to be part of the syndrome - yes or no? Briefly defend your answer - you may use bullet points.
2. How are the following three types of cancer similar? You should be able to answer this question with one sentence!
- retinoblastoma type 1 (a p-53-related cancer)
- inherited stomach cancer
- BRCA1 breast cancer
3. Genetic changes that can cause cancer include hypermethylation of a promoter, change in chromosome number, copy number variants, single-base changes, and changes in chromosome structure.
True
False
4. Why is the cell surface marker CD133 an appealing drug target? You may use bullet points to answer the question.
Explanation / Answer
1) Hutchinson-Gilford progeria syndrome does not lead to cancer. This can be explained by following points
a) Wnt--catenin is downregulated so there is decreased tumorigenesis
b) p53 is activated which inhibits tumorigenesis. It also leads to apoptosis.
c) Mutations in human LMNA gene lead to premature aging due to incresed apoptosis.
d) Presence of short telomers also inhibit tumorigenesis.
2) The three types of cancer are similar in one respect i.e, these are caused by the inactivation or loss of function of tumour suppressor genes like RB1, p53 and BRC1.
3) True. Genetics changes cause cancer.
Hypermethylation of promoters can cause silencing of TUMOUR SUPPRESSOR GENES.
Single base changes or point mutations can alter the amino acid sequence of an oncoprotein and lead to its complete activation. The oncoprotein will be always in active form e.g ras proteins.
Changes in chromosome structure like in case of chromosomal translocation or deletions can lead to activation of proto-oncogenes thus leading to cancer e.g Chronic myelogenous leukemia, Acute myelogenous leukemia, wilm's tumour, retinoblastoma, etc
Copy number variants or gene amplification can lead to activation of proto-oncogenes e.g N-myc in neuroblastoma.
Changes in chromosome number or aneuploidy have not yet been reported in any form of cancer. Although other syndromes have been reported e.g Down;s syndrome, Turner syndrome, etc.
4) CD 133 is an appealing drug target due to following reasons
a) CD133 is invoved in cell self-renewal and tumorigenesis. CD133 expression has been shown to be essential for self-renewal function and tumorigenesis in certain cell types.
b) CD 133 has been shown to be involved in metastasis due to increased expression.
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