Chapter 19, The Genetics of Cancer Video Solutions, Essentials of Genetics

Problem 1

In this chapter, we focused on cancer as a genetic disease, with an emphasis on the relationship between cancer, the cell cycle, and DNA damage, as well as on the multiple steps that lead to cancer. At the same time, we found many opportunities to consider the methods and reasoning by which much of this information was acquired. From the explanations given in the chapter
(a) How do we know that malignant tumors arise from a single cell that contains mutations?
(b) How do we know that cancer development requires more than one mutation?
(c) How do we know that cancer cells often contain defects in
DNA repair?

Marisa A

Numerade Educator

04:02

Problem 2

These concepts relate to the multiple ways in which genetic alterations lead to the development of cancers. The sixth concept states that epigenetic effects including DNA methylation and histone modifications contribute to the genetic alterations leading to cancer. Write a short essay describing how epigenetic changes in cancer cells contribute to the development of cancers.

Courtney Burson

Numerade Educator

00:42

Problem 3

What is the relationship between signal transduction and cellular
proliferation?

Sam Limsuwannarot

Numerade Educator

04:08

Problem 4

Where are the major regulatory points in the cell cycle?

John Barone

Numerade Educator

04:25

Problem 5

Describe kinases and cyclins. How do they interact to cause cells to move through the cell cycle?

Dr. Anas Syed

Numerade Educator

00:28

Problem 6

What is the difference between saying that cancer is inherited and saying that the predisposition to cancer is inherited?

Sam Limsuwannarot

Numerade Educator

00:28

Problem 7

What is the difference between saying that cancer is inherited and saying that the predisposition to cancer is inherited?

Sam Limsuwannarot

Numerade Educator

00:25

Problem 8

What is apoptosis, and under what circumstances do cells
undergo this process?

Sam Limsuwannarot

Numerade Educator

01:30

Problem 9

Define tumor-suppressor genes.Why is a mutation in a single copy of a tumor-suppressor gene expected to behave as a recessive gene?

Lottie Adams

Numerade Educator

07:07

Problem 10

Describe the ways in which the p53 tumor-suppressor protein can be activated in normal cells.

Sana Riaz

Numerade Educator

07:07

Problem 11

How does the p53 tumor-suppressor protein control cell-cycle checkpoints?

Sana Riaz

Numerade Educator

01:15

Problem 12

If a cell suffers damage to its DNA while in S phase, how can this damage be repaired before the cell enters mitosis?

Mikayla Stephens

Numerade Educator

02:15

Problem 13

Distinguish between oncogenes and proto-oncogenes. In what ways can proto-oncogenes be converted to oncogenes?

Hannah Vigran

Numerade Educator

Problem 14

Of the two classes of genes associated with cancer, tumor-suppressor genes and oncogenes, mutations in which group can be considered gain-of-function mutations? In which group are the loss-of-function mutations? Explain.

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00:41

Problem 15

How do translocations such as the Philadelphia chromosome con- tribute to cancer?

Sam Limsuwannarot

Numerade Educator

02:46

Problem 16

What are the differences between cancer driver mutations and passenger mutations? How can a passenger mutation become a driver mutation?

Ramesh Singh

Numerade Educator

00:35

Problem 17

What are the most significant environmental agents that contribute to human cancers?

Mishal Gul

Numerade Educator

04:34

Problem 18

How do normal cells protect themselves from accumulating mutations in genes that could lead to cancer? How do cancer cells differ from normal cells in these processes?

Heather Thornton

Numerade Educator

00:56

Problem 19

What is loss of heterozygosity, and how does this process contribute to the development of cancers?

Sam Limsuwannarot

Numerade Educator

01:57

Problem 20

Explain how environmental agents such as chemicals and radiation cause cancer.

Sharfa Farzandh

Numerade Educator

02:49

Problem 21

Radiotherapy (treatment with ionizing radiation) is one of the most effective current cancer treatments. It works by damaging DNA and other cellular components. In which ways could radiotherapy control or cure cancer, and why does radiotherapy often have significant side effects?

Aja S

Numerade Educator

01:59

Problem 22

Genetic tests that detect mutations in the $B R C A 1$ and $B R C A 2$ oncogenes are widely available. These tests reveal a number of mutations in these genes-mutations that have been linked to familial breast cancer. Assume that a young woman in a suspected breast cancer family takes the $B R C A 1$ and $B R C A 2$ genetic tests and receives negative results. That is, she does not test positive for the mutant alleles of $B R C A I$ or $B R C A 2$. Can she consider herself free of risk for breast cancer?

Alexander Clippinger

Numerade Educator

04:49

Problem 23

What is the cancer stem cell hypothesis?

Sana Riaz

Numerade Educator

00:28

Problem 24

Explain the differences between a benign and malignant tumor.

Sam Limsuwannarot

Numerade Educator

00:51

Problem 25

As part of a cancer research project, you have discovered a gene that is mutated in many metastatic tumors. After determining the DNA sequence of this gene, you compare the sequence with those of other genes in the human genome sequence database. Your gene appears to code for an amino acid sequence that resembles sequences found in some serine proteases. Conjecture how your new gene might contribute to the development of highly invasive cancers.

Sam Limsuwannarot

Numerade Educator

04:08

Problem 26

A study by Bose and colleagues (1998. Blood 92: 3362-3367) and a previous study by Biernaux and others [1996. Bone Marrow Transplant 17: (Suppl. 3) $\mathrm{S} 45-\mathrm{S} 47$ ] showed that $B C R-A B L$ fusion gene transcripts can be detected in 25 to 30 percent of healthy adults who do not develop chronic myelogenous leukemia (CML). Explain how these individuals can carry a fusion gene that is transcriptionally active and yet do not develop CML.

Karen Song

Numerade Educator

01:19

Problem 27

Those who inherit a mutant allele of the $R B 1$ tumor-suppressor gene are at risk for developing a bone cancer called osteosarcoma. You suspect that in these cases, osteosarcoma requires a mutation in the second $R B 1$ allele, and you have cultured some osteosarcoma cells and obtained a cDNA clone of a normal human $R B 1$ gene. A colleague sends you a research paper revealing that a strain of cancer-prone mice develops malignant tumors when injected with osteosarcoma cells, and you obtain these mice. Using these three resources, indicate which experiments you would perform to determine the following:
(a) whether osteosarcoma cells carry two $R B 1$ mutations,
(b) whether osteosarcoma cells produce any pRB protein,
(c) if the addition of a normal $R B 1$ gene will change the cancercausing potential of osteosarcoma cells.

Mikayla Stephens

Numerade Educator