What Science Knows about Cancer: Course Guidebook

174 Pages·2013·1.93 MB·English

by  David Sadava

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—The Los Angeles Times S about Cancer
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“A serious force in American education.” c
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—The Wall Street Journal K
Course Guidebook
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u Professor David Sadava
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City of Hope Medical Center and The Claremont Colleges
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Professor David Sadava is Adjunct Professor of Cancer Cell
Biology at the City of Hope Medical Center. He also is the
Pritzker Family Foundation Professor of Biology, Emeritus,
at Claremont McKenna, Pitzer, and Scripps, three of The
Claremont Colleges. At Claremont, he has twice won the
Huntoon Award for superior teaching. Professor Sadava
is the author or coauthor of more than 55 peer-reviewed
scientific research papers and five books, including two
recent biology textbooks. He received his Ph.D. in Biology
from the University of California, San Diego.
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David Sadava, Ph.D.
Adjunct Professor of Cancer Cell Biology
and Pritzker Family Foundation
Professor of Biology, Emeritus
City of Hope Medical Center
and The Claremont Colleges
P
rofessor David Sadava is Adjunct Professor
of Cancer Cell Biology at the City of Hope
Medical Center. He also is the Pritzker
Family Foundation Professor of Biology, Emeritus, at Claremont McKenna,
Pitzer, and Scripps, three of The Claremont Colleges. Professor Sadava
graduated from Carleton University as the science medalist, earning a
B.Sc. with fi rst-class honors in Biology and Chemistry. A Woodrow Wilson
Fellow, he received a Ph.D. in Biology from the University of California,
San Diego.
Following postdoctoral research at the Scripps Institution of Oceanography,
Professor Sadava joined the faculty at Claremont, where he twice won the
Huntoon Award for superior teaching, in addition to receiving numerous
other faculty honors. He has taught undergraduate courses in general biology
and biotechnology and one of the fi rst advanced undergraduate courses in
cancer biology. He also has been a visiting professor at the University of
Colorado and at the California Institute of Technology.
Professor Sadava has held numerous research grants and has written
more than 55 peer-reviewed scientifi c research papers, many with his
undergraduate students as coauthors. A laboratory scientist, his research
concerns resistance to chemotherapy in human lung cancer, with a view to
developing new plant-based medicines to treat this disease.
He is the author or coauthor of fi ve books, including the recently published
ninth edition of a leading biology textbook, Life: The Science of Biology, as
well as a new biology textbook, Principles of Life.
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Professor Sadava also has produced Understanding Genetics: DNA, Genes,
and Their Real-World Applications with The Great Courses. ■
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Table of Contents
INTRODUCTION
Professor Biography ............................................................................i
Course Scope .....................................................................................1
LECTURE GUIDES
LECTURE 1
Cancer Is an Ongoing Challenge .......................................................5
LECTURE 2
Cancer Is a Major Burden to Society ................................................12
LECTURE 3
Discovering Causes of Cancer in Populations .................................18
LECTURE 4
Some Causes of Cancer in Populations ...........................................25
LECTURE 5
DNA Is the Key to Understanding Cancer ........................................31
LECTURE 6
How Does DNA Change to Initiate Cancer? .....................................38
LECTURE 7
How Do We Know If Something Causes Cancer? ...........................44
LECTURE 8
How Do Normal Cells Function? ......................................................50
LECTURE 9
What Is Different about Cancer Cells? .............................................56
LECTURE 10
How Do Tumors Grow? ....................................................................63
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Table of Contents
LECTURE 11
How Tumors Spread and Thrive .......................................................69
LECTURE 12
What Are Tumor Viruses? .................................................................75
LECTURE 13
How Do Tumor Viruses Cause Cancer? ...........................................81
LECTURE 14
How Do Cancer-Causing Genes Work? ...........................................87
LECTURE 15
Can Cancer Be Inherited? ................................................................93
LECTURE 16
How Do Normal Genes Suppress Tumors? .....................................99
LECTURE 17
How Do Genetic Changes Result in Cancer? ................................105
LECTURE 18
Treating Cancer with Surgery .........................................................111
LECTURE 19
Treating Cancer with Radiation ......................................................117
LECTURE 20
Treating Cancer with Drugs ............................................................123
LECTURE 21
How Do Drugs Attack Cancer? .......................................................129
LECTURE 22
Frontiers of Cancer Treatment........................................................135
LECTURE 23
Can Screening for Cancer Be Useful? ...........................................141
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Table of Contents
LECTURE 24
Can Cancer Be Prevented?............................................................147
SUPPLEMENTAL MATERIAL
Glossary .........................................................................................153
Bibliography ....................................................................................163
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What Science Knows about Cancer
Scope:
T
here are few words in any language that strike as much fear as the
word “cancer.” One person in three develops malignant cancer in his
or her lifetime, and one out of four dies from it. The aim of this course
is to explain the science that underlies this disease. As you learn about how
cancer works to subvert the body’s normal functioning, you will see how
cancer can be treated and even prevented.
The fi rst part of the course sets the stage, describing the challenge that cancer
poses to humanity. Lectures 1 and 2 outline where we have been and where
we are. Because cancer typically strikes older people, it was relatively rare
until the past century. People thought—and many still think—that cancer
was caused by an imbalance of bodily fl uids or was a punishment by a deity.
More recently, explanations of cancer based on the chemistry and physics
of cells in the body have taken hold. The U.S. government optimistically
declared a 10-year “war on cancer” in 1972. Clearly, it failed and has
turned into a war of attrition. After heart disease, cancer is still the second
leading cause of death, with lung cancer leading the way. Lectures 3 and 4
deal with epidemiology, the study of diseases in populations. It seems that
every day, the results of long-term studies of groups of people point to new
links between diet, environmental exposure, or lifestyle and cancer. The
most obvious of these culprits is tobacco smoking, which is implicated in
about one-third of all cancer. Less clear are the effects of various aspects
of diet, where data are often confl icting. Even less clear is the link between
personality and cancer.
More direct information on the causes of cancer is revealed in the second
part of the course. In Lecture 5, we enter the cell and focus on its genetic
material, DNA. This is where a lot of cancer begins. The human genome has
several billion chemical “beads” making up long chains of DNA in every
one of the trillions of cells in the body. Many of the instructions in DNA are
expressed as proteins. Mutations are changes in the DNA “beads.” Every
day, thousands of these changes occur spontaneously in many cells, and they
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can result in altered proteins with changes in cell functions. As Lecture 6
points out, most cancer-causing agents (carcinogens) cause mutations in
DNA. We are exposed to thousands of these agents all the time, ranging from
ultraviolet radiation from the Sun, to naturally occurring chemicals in the
bodies of plants and animals that we eat, to industrial pollutants. Cells have
ways to repair the DNA mutations before cancer starts. But too often, the
damage overwhelms the repair systems, and the mutations are permanent.
Lecture 7 describes how scientists have developed lab tests on simple
organisms to try to sort out cancer-causing agents from harmless ones.
Unfortunately, the results of these tests are often unclear and may not apply
to humans—so people and governments apply risk analysis, where costs and
benefi ts of exposure are weighed and decisions are made.
The third part of the course describes the features of cancer as a disease
of cells. In Lectures 8 and 9, cells in general and cancer cells in particular
are introduced. All cells in the body—whether on the skin or inside the
heart—have basically the same overall structure, with the entire DNA
genome enclosed in a nucleus. When a cell’s DNA is changed, its functions
can change, and cancer can be initiated. This results in cell changes such
as constant cell reproduction (so that the tumor grows); changes in the cell
surface (so that cancer cells are less “sticky”); and a general dedifferentiation,
or loss of specialized appearance and function. While a tumor with billions
of cells may arise from a single cell, the cells keep on changing so that only
some of the cells may retain the ability to keep growing. These are called
cancer stem cells. In Lectures 10 and 11, the growth and spread of cancer
are described in cellular terms. Tumors can be benign or malignant. Benign
tumors grow to a limited size and typically stop as a ball of cells; they do not
spread but can cause signifi cant illness when they grow inside an organ such
as the brain. Malignant tumors can metastasize, or spread by breaking off
some cells and sending them throughout the body via the blood or lymphatic
systems. Tumors send chemical signals to nearby blood vessels to sprout
branches to nourish the tumor, a process called angiogenesis. As a tumor
grows and spreads unchecked, it places an increasing burden on the body’s
functions, leading to serious illness and death.
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p The fourth part of the course describes the scientifi c discoveries about
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S cancer deep inside cells. Some of these have come from cancer viruses and
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