Introduction to Cancer

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Questions and Answers

What is a necessary condition for a gene to be cancer-inducing?

The gene must be an oncogene

Both copies of the gene must be affected (correct)

The gene must be a tumor suppressor gene

One copy of the gene must be affected

What is the primary function of the immune system?

To produce antibodies and cytokines

To surveil the human body to destroy viruses and foreign cell types (correct)

To destroy tumor cells

To inhibit T cells

Which cells of the immune system engulf and destroy foreign particles?

T lymphocytes and natural killer cells

B cells and macrophages

Macrophages and natural killer cells (correct)

T lymphocytes and B cells

What is the reason why normal human cells have a finite ability to undergo mitosis?

Due to the shortening of telomeres Signup and view all the answers

What enables cancer cells to exceed Hayflick's limit and continue to undergo mitosis?

The ability to elongate telomeres using telomerase Signup and view all the answers

What is the role of PDL-1 and PDL-2 antigens in cancer cells?

To inhibit T cells that would normally attack cancer cells Signup and view all the answers

What is the definition of metastasis?

The process by which tumor cells move from the primary tumor to a different organ via lymph and/or blood Signup and view all the answers

What is the function of the tumor suppressor gene p53?

To stop the cell cycle upon detection of DNA damage Signup and view all the answers

What is the term for the state of being able to metastasize?

Metastatic Signup and view all the answers

How do normal cells respond to abundant DNA damage and other cellular stresses?

They initiate apoptosis Signup and view all the answers

What is a hallmark of cancer cells?

The ability to proliferate due to over-active oncogenes Signup and view all the answers

What is the characteristic of benign tumors?

They are unable to invade neighboring tissue and metastasize Signup and view all the answers

How do cancer cells divert metabolites?

By diverting metabolites for useful processes such as mitosis Signup and view all the answers

What is the most common secondary site for cancer metastasis?

Lung and liver Signup and view all the answers

What is the primary tumor growth characterized by?

Cells grow uncontrollably until they become a mass Signup and view all the answers

What is the difference between normal cells and cancer cells in terms of glucose breakdown?

Normal cells break down glucose to pyruvate, while cancer cells break it down to lactate Signup and view all the answers

What is the primary cause of cancer in the human body?

Abnormal cell division in a specific part of the body Signup and view all the answers

What type of cancer arises from epithelial tissue in organs or glands?

Carcinoma Signup and view all the answers

What is the effect of an activating mutation on a gene?

It causes the gene to be expressed at the wrong time, at the wrong level, or with a new function Signup and view all the answers

What type of mutation is inherited from parents and present in germ cells?

Germline mutation Signup and view all the answers

What is the Two Hit Hypothesis in relation to genetic mutations?

Both alleles of a gene must be mutated for cancer to occur Signup and view all the answers

What is the main difference between somatic and germline mutations?

Germline mutations are inherited, while somatic mutations are acquired Signup and view all the answers

What is the increased risk associated with inheriting a BRCA1/2 mutation?

Breast cancer Signup and view all the answers

What is the type of cancer that arises from connective tissue?

Sarcoma Signup and view all the answers

What is the main premise of the scientific theory of evolution?

That all living organisms on Earth descended from a common ancestor Signup and view all the answers

What is the primary mechanism driving the process of evolution?

Natural selection Signup and view all the answers

Which of the following is a key principle of Darwinian evolution?

Variation exists among individuals within a population Signup and view all the answers

What is the term for a trait that improves an organism's chance of survival and reproduction?

Adaptation Signup and view all the answers

What is the ultimate outcome of natural selection acting on a population over time?

The population evolves into a new species Signup and view all the answers

What is the estimated percentage of species that have ever lived on Earth that have become extinct?

99% Signup and view all the answers

Which of the following is a key aspect of gradualism?

Species originate through a gradual change of adaptations Signup and view all the answers

What is the term for the process by which an organism's genes and their frequencies change over time?

Evolution Signup and view all the answers

What is the primary mechanism by which genetic changes occur in punctuated equilibrium?

Rapid genetic changes in response to environmental pressures Signup and view all the answers

What is the primary goal of artificial selection in genetic engineering?

To create genetically modified organisms with desired traits Signup and view all the answers

What is the primary difference between inbreeding and hybridization in genetic engineering?

Inbreeding involves breeding within a species, while hybridization involves crossing two species Signup and view all the answers

What is the primary risk associated with inbreeding in genetic engineering?

The increased risk of recessive genetic disorders Signup and view all the answers

What is the primary purpose of cloning in genetic engineering?

To create an exact genetic copy of an organism Signup and view all the answers

What is the primary characteristic of punctuated equilibrium in terms of the fossil record?

A rapid and episodic record of evolutionary changes Signup and view all the answers

What is the primary difference between genetic engineering and traditional breeding practices?

Genetic engineering involves the use of biotechnology to modify genes, while traditional breeding practices rely on natural selection Signup and view all the answers

What is the primary advantage of genetic engineering over traditional breeding practices?

Genetic engineering is faster and more precise than traditional breeding practices Signup and view all the answers

Study Notes

Cancer

Cancer is caused by an uncontrolled division of abnormal cells in a part of the body.
It is caused by an accumulation of detrimental variations in the genome over the course of a lifetime.

Types of Cancer

There are four main types of cancer:
- Carcinoma: Arises in epithelial tissue that is found in the internal and external lining of the body.
- Sarcoma: Arises from connective tissue that is found in bones, tendons, cartilage, muscle, and fat.
- Leukemia: Cancers of the blood that originate in bone marrow.
- Lymphoma: Cancers of the lymph system.

Mutations

Activating mutations: Cause the gene to be expressed at the wrong time, at the wrong level, or with a new function.
Inactivating mutations: Cause reduced function of a gene (less RNA or protein is made).

Somatic and Germline Mutations

Somatic mutations: Acquired by a somatic cell (all cells except eggs or sperm) that are passed on to daughter cells during cell proliferation.
Germline mutations (inherited mutations): Present in a germ cell (egg or sperm) and are inherited by offspring.

Two Hit Hypothesis

For a gene to be cancer-inducing, both copies of the gene must be affected.
The second "hit" may alter the DNA (mutation) or alter the expression of the DNA (epigenetic).

Hallmarks of Cancer Cells

Cancer cells can greatly exceed "Hayflick's limit" and continue to undergo mitosis.
Cancer cells are able to do this because they can elongate their telomeres using an enzyme called telomerase.

Tumor Suppressor Genes

A Tumor Suppressor Gene, p53, functions as a central regulator of cell death because it stops the cell cycle upon detection of DNA damage.

Cancer Cell Characteristics

Cancer cells have the ability to proliferate due to the aforementioned Hallmarks 1--4 as well as to over-active oncogenes.
Cancer cells have altered metabolism, and are able to divert metabolites for useful processes such as mitosis.
Cancer cells can protect themselves by inhibiting T cells that would normally attack these cancer cells by having the PDL-1 (Programmed Death Ligand -1) or PDL-2 antigen which deflects the immune response.

Metastasis

The process by which tumor cells move from the primary tumor to a different organ via lymph and/or blood.
Cancer cells can metastasize to a secondary site, such as the lung and liver.

Evolution and Genetic Engineering

Evolution: Change in populations over time.
Important principles of Darwinian Evolution include variation, heritability, and reproductive advantage.
Genetic Engineering: Changing the DNA in living organisms to create something. These organisms are called Genetically Modified Organism (GMO).

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Description

Learn about the causes of cancer, and the different types of cancer, including carcinoma, sarcoma, and leukemia.