30 Questions
What is the result of the process of carcinogenesis?
Transformation of normal cells to neoplastic cells
What is a carcinogen?
An agent directly involved in causing cancer
How many classes of carcinogenic agents can be identified?
Three
What is the multistep carcinogenesis hypothesis?
More than one carcinogen is necessary for the complete neoplastic transformation
What is the outcome of genetic abnormalities in carcinogenesis?
Permanent genetic alterations
What is the purpose of understanding the multistep theory of neoplasia?
To understand the causes of cancer
What is the 'hit-and-run' situation in the context of carcinogenesis?
The presence of the carcinogen is not required for neoplastic behaviour once it is established
What are the two major steps in the transformation of cells in experimental carcinogenesis?
Initiation and Promotion
What is the process by which neoplasms arise from single cells that have become transformed by cumulative mutational events?
Clonal evolution model
What are the genetic alterations involved in the development of human tumours?
Genetic alterations of oncogenes and tumour suppressor genes
What is the result of the progression step in the development of tumours?
The malignant phenotype
What are the exceptions to the 'hit-and-run' situation where the evidence of the specific causative agent(s) is found in the eventual tumours?
Some suspected carcinogenic viruses and some insoluble substances
What is responsible for the initiation and long-term maintenance of the tumor?
Cancer stem cells
According to Vogelstein's theory of colonic carcinogenesis, how many DNA changes are typically required for a cell to become fully cancerous?
6-7
What type of genes can be mutated or lost in colon cancer development?
Both oncogenes and tumor-suppressor genes
What is the name of the gene associated with adenomatosis polyposis coli?
APC
What is the term for the process by which a benign neoplasm becomes a carcinoma?
Carcinogenesis
How many classes of genes can be mutated to cause cancer?
4
What is a characteristic of neoplasms?
They are clonal proliferations
What increases with the number of cell divisions experienced by a cell?
The probability of neoplastic transformation
What is the result of each successive mutation in the clonal evolution model?
A growth advantage to the cell
What is a characteristic of cancer stem cells (CSCs)?
They have the ability to self-renew and generate diverse tumour cells
What is a potential consequence of cancer stem cells (CSCs) having different sensitivities to radiation or chemotherapy?
Increased risk of tumour relapse
In which types of cancer have cancer stem cells (CSCs) been identified?
In breast cancer, colon cancer, leukaemia, prostate cancer, melanoma, pancreatic cancer, and some malignant brain tumours
What is the normal activity of growth-promoting proto-oncogenes?
To promote cell proliferation
What is the effect of a single mutant allele of a growth-promoting proto-oncogene?
May affect cell phenotype
What is the result of a loss-of-function mutation in a tumour suppressor gene?
Increased cell proliferation
What is the effect of gain-of-function mutations in genes whose products suppress apoptosis?
Enhanced cell survival
What is the consequence of loss-of-function mutations in DNA repair genes?
Impaired ability to recognize and repair genetic damage
How many hallmarks of cancer are described in the 2011 Cell paper by Hanahan and Weinberg?
13
This quiz assesses your understanding of the multistep theory of carcinogenesis, including the cellular and molecular events involved, genetic abnormalities, and hallmarks of cancer. It's based on the learning objectives for Prof. Thidar Aung's course at Manipal University College Malaysia. Test your knowledge of the process that transforms normal cells into neoplastic cells!
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