Week 4

Question 1

What are mutations?

Answer 1

Mutations are a change in the nucleotide sequence of the open reading frame (coding region) of a gene.

Question 2

Why are promotors and transcription factors important in the development of cancer?

Answer 2

Mutations in the promotor regions of genes can lead to misregulation of gene expression. Increasing transcription factor activity and transcription of a certain gene can also contribute to transformation and tumor formation. Mutating the promotor region could prevent repressor proteins from binding to the DNA’s control region. Under normal conditions, RNA polymerase would not be able to transcribe the gene, but once it is mutated, that gene will be expressed more rapidly than normal.

Question 3

Name and briefly describe the three main categories of genes that are mutated in cancer cells

Answer 3

Genes controlling apoptosis (tied to the DNA damage pathways).

Genes that regulate the cell cycle (cyclins, CDKs, etc)

Location-signaling gene…or body position gene.

Question 4

In cancer biology, what is meant by the term “transformation”?

Answer 4

Transformation = the process that converts a normal cell into a cancer cell. This occurs because of mutations in the three categories of genes.

Question 5

What is Carcinogenesis? How is it different from transformation?

Answer 5

Carcinogenesis is the process of developing a tumor. In contrast, transformation is the process of changing noncancerous cells into cancer cells. Transformation is a precursor to carcinogenesis.

Question 6

Define the term apoptosis.

Answer 6

Scheduled/programmed cell death.
1. Apoptosis follows a set pattern. It is not spontaneous destruction. If the cell just exploded it would release a host of toxic chemicals and enzymes that would harm the surrounding cells.
2. Visual signs of apoptosis include extensive membrane blebbing
3. Necrotic cell death is caused by mechanical damage, lack of oxygen/nutrients…something going wrong.

Question 7

Describe the origin of the cancer sarcoma

Answer 7

Sarcomas - from tissues of mesodermal origin

Question 8

Compare solid tumors to liquid tumors

Answer 8

Solid: Attached to a specific location and develop as a ‘rigid’ mass. A mass of solid cancer cells that grow in organ systems and can appear anywhere in the body, like breast cancer

Liquid: Circulating forms of tumors that originate from hematopoietic stem cell lineages. cancers that develop in the blood, bone marrow, or lymph nodes, and include leukemia, lymphoma, and myeloma

Question 9

How are mutations involved in the development of cancer?

Answer 9

If key cancer regulation genes are mutated it can result in a cell that replicates in a rapid, uncontrollable manner to form a tumor. Mutations generally take a long period to cause cancer. This is why cancer usually presents itself in older populations.

Question 10

What are transcription factors?

Answer 10

Transcription factors are important modulators of gene expression. They are proteins that assemble on a eukaryotic chromosome, either allowing RNA polymerase to initiate transcription or preventing RNA polymerase from binding to the promotor region.

Question 11

What are promotor regions?

Answer 11

a portion of the DNA sequence to which the RNA polymerase binds in order to initiate transcription.

Question 12

Describe the process of apoptosis presented in lecture

Answer 12

1. External signal binds to a receptor protein
2. Downstream signals activate apoptotic pathways
3. Transcription factors in the nucleus that control apoptotic activity are activated.

Question 13

Describe the origin of the cancer carcinomas

Answer 13

Carcinomas - from tissues of endo or ectodermal origin

Question 14

Describe the origin of the cancer adenomas

Answer 14

Adenomas - from tissues in glands

Question 15

Describe the origin of the cancer lymphomas

Answer 15

Lymphomas - originate in and occupy lymph tissues

Question 16

Describe the origin of the cancer leukemias

Answer 16

Leukemias - Originates in bone marrow cells and circulates in blood

Question 17

What are hematopoietic cells?

Answer 17

Hematopoietic stem cells are specialized stem cells that may differentiate into any blood cell: White blood cell, red blood cell, or platelet. “Relating to, or involved in the formation of the blood”.

Question 18

Diagram the cell cycle and explain how cyclins are involved in regulating the cell cycle

Answer 18

*Reference slides

Question 19

Describe the difference between prokaryotic and eukaryotic mRNAs

Answer 19

Prokaryotic mRNAs contain multiple open reading frames and code for multiple proteins, while eukaryotic mRNAs contain only one open reading frame and undergo post-transcriptional editing (splicing out introns and connecting exons).

Question 20

Tumor suppressor protein—important regulators of the cell cycle.

Answer 20

An example of a tumor suppressor protein is P53. It detects damaged DNA. When bound to damaged DNA, it becomes activated and initiates apoptotic pathways.
Over half of all cancers involve mutations in P53.

Question 21

What are oncogenes? How do they relate to cancer development?

Answer 21

Proteins that are positive regulators in cancer cells. They are derived from normal positive regulators that have become mutated to be overly active or that are present in excess, and they stimulate the cancer cells to divide more often. Oncogenes signal transduction pathways that stimulate cell division.

Question 22

What is metastasis?

Answer 22

The development of secondary malignant growths at a distance from a primary site of cancer.

Question 23

How can benign tumors harm their local tissue?

Answer 23

Even though benign tumors are constrained by connective tissue and cannot metastasize, they can still harm local cells and tissue by putting pressure on vital structures such as blood vessels or nerves.

Question 24

Monoclonal antibodies…how are they used in targeted cancer treatment?

Answer 24

Identify the proteins produced by tumor cells. Develop an antibody that targets the cancerous proteins.
Use a plasmid expression vector to engineer the antibody in E.coli bacteria.
Proteins produced by mutated cancer cells are recognized as “non-self” proteins

Question 25

Cancer Staging—classifying cancer severity

Answer 25

Identifying cancer in an early stage increases the probability of successful treatment.
Mitotic indices such as tumor size, growth rate, location, and invasivity impact cancer staging. A large tumor mass may be classified as stage 1 or stage 2 if it is not growing quickly.