Multistep Theory of Carcinogenesis

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What is the result of the process of carcinogenesis?

Transformation of neoplastic cells to normal cells

Inhibition of cellular growth and division

Removal of genetic alterations from normal cells

Transformation of normal cells to neoplastic cells (correct)

What is a carcinogen?

A microbial agent that cures cancer

A substance that prevents cancer

A radioactive substance that kills cancer cells

An agent directly involved in causing cancer (correct)

How many classes of carcinogenic agents can be identified?

One

Four

Three (correct)

Two

What is the multistep carcinogenesis hypothesis?

More than one carcinogen is necessary for the complete neoplastic transformation Signup and view all the answers

What is the outcome of genetic abnormalities in carcinogenesis?

Permanent genetic alterations Signup and view all the answers

What is the purpose of understanding the multistep theory of neoplasia?

To understand the causes of cancer Signup and view all the answers

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 Signup and view all the answers

What are the two major steps in the transformation of cells in experimental carcinogenesis?

Initiation and Promotion Signup and view all the answers

What is the process by which neoplasms arise from single cells that have become transformed by cumulative mutational events?

Clonal evolution model Signup and view all the answers

What are the genetic alterations involved in the development of human tumours?

Genetic alterations of oncogenes and tumour suppressor genes Signup and view all the answers

What is the result of the progression step in the development of tumours?

The malignant phenotype Signup and view all the answers

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 Signup and view all the answers

What is responsible for the initiation and long-term maintenance of the tumor?

Cancer stem cells Signup and view all the answers

According to Vogelstein's theory of colonic carcinogenesis, how many DNA changes are typically required for a cell to become fully cancerous?

6-7 Signup and view all the answers

What type of genes can be mutated or lost in colon cancer development?

Both oncogenes and tumor-suppressor genes Signup and view all the answers

What is the name of the gene associated with adenomatosis polyposis coli?

APC Signup and view all the answers

What is the term for the process by which a benign neoplasm becomes a carcinoma?

Carcinogenesis Signup and view all the answers

How many classes of genes can be mutated to cause cancer?

4 Signup and view all the answers

What is a characteristic of neoplasms?

They are clonal proliferations Signup and view all the answers

What increases with the number of cell divisions experienced by a cell?

The probability of neoplastic transformation Signup and view all the answers

What is the result of each successive mutation in the clonal evolution model?

A growth advantage to the cell Signup and view all the answers

What is a characteristic of cancer stem cells (CSCs)?

They have the ability to self-renew and generate diverse tumour cells Signup and view all the answers

What is a potential consequence of cancer stem cells (CSCs) having different sensitivities to radiation or chemotherapy?

Increased risk of tumour relapse Signup and view all the answers

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 Signup and view all the answers

What is the normal activity of growth-promoting proto-oncogenes?

To promote cell proliferation Signup and view all the answers

What is the effect of a single mutant allele of a growth-promoting proto-oncogene?

May affect cell phenotype Signup and view all the answers

What is the result of a loss-of-function mutation in a tumour suppressor gene?

Increased cell proliferation Signup and view all the answers

What is the effect of gain-of-function mutations in genes whose products suppress apoptosis?

Enhanced cell survival Signup and view all the answers

What is the consequence of loss-of-function mutations in DNA repair genes?

Impaired ability to recognize and repair genetic damage Signup and view all the answers

How many hallmarks of cancer are described in the 2011 Cell paper by Hanahan and Weinberg?

13 Signup and view all the answers