How Do We Inherit Our Biological Characteristics

How Do We Inherit Breast Cancer?

Shelly Peretz
Science Department Chairperson
Thornridge High School

Office Phone: 708-225-4585

Breast Cancer Awareness Emblem taken from Ethical, Legal, and Social Issues in Science Project, Lawrence Berkeley National Laboratory


Mary Jane Smith is a 42 year old woman who has been diagnosed and treated for breast cancer. Mary Jane has a married sister, Samantha who has three children--two daughters, Fran and Irene, and a son, Don; all three are in their teens. Mary Jane and Samantha's mother died of breast cancer at the age of 48.

Mary Jane's doctor is a breast cancer researcher at a local university hospital. She invited Mary Jane to have a genetic test to determine if her breast cancer was the inheritable type. Test results showed that Mary Jane has a gene called BRCA-2 which accounts for about 2% of the breast cancer cases diagnosed each year. The BRCA-2 test was not available while Mary Jane and Samantha's mother was alive, so there is no way to tell if Mary Jane inherited the gene from her mother or her father. Mary Jane has the gene, so there is a 50% chance for each of her children that they have inherited the gene from her. This gene triggers breast cancer in both males and females, and 85% of females having the BRCA-2 gene develop cancer. Athough only 1% of breast cancer occurs in men, most of these cases occur in men with the BRCA-2 gene.

Research on the BRCA-2 gene is very new, and the doctor asks Mary if she can study the family to determine their risk for this disease. She needs the cooperation of all family members in order to include them in the study.

Mary Jane knows that early detection is extremely important for survival. She has recommended that all family members be tested.

Samantha is 40 years old and does not want to be tested. However, her daughters are interested in participating in the research and knowing their risk for breast cancer. Samantha's son does not have an opinion. If any of the children has the gene, Samantha will know that they have inherited it from her.

Classroom Scenario written by Sylvia Spengler ( and Catherine Pinkas( , Ethical, Legal, and Social Issues in Science, Lawrence Berkeley National Laboratory.

Your assignment for the next three weeks will be to investigate this disease and prepare a "story book" about the disease. The genetics counseling community ascribes to a belief in non-directive counseling. That is, they feel that it is their duty to provide all of the information that is available and desired by a family so that they can make the decisions that are appropriate to them based on their own cultural, moral, religious, etc. beliefs.

Your investigation should include medical information important for people with this disease so that they can live a healthy and prolonged life. This might include:

Each image must have a caption. The presentation will be given using ClarisWorks® or Microsoft PowerPoint® presentation software. It should be written such that someone else could view the presentation and understand the key points without an accompanying verbal explanation.

You may not violate copyright laws. Any images or other resources retrieved from the internet and used in your presentation must be accompanied by a reference telling where it was obtained.

Technology Support

Netscape Basics
Here you can find a wealth of helpful information about your Netscape software and how to overcome any problems you might encounter with it.
Finding Information
Finding what you want on the Internet can be like looking for a needle in a haystack. Online search tools help you track down whatever it is you're looking for.

Helpful Exercises

The following exercises were designed to help you understand human genetic diseases, including the medical facts, diagnosis, probable course of the disorder, and the available management. While these exercises are, of course, optional, you are strongly encouraged to complete them:

Guidelines for Reporting and Writing About People with Disabilities
The University of Kansas and other national associations have endorsed a a set of clear guidelines to help you make better choices in terms of language and portrayal. The "Guidelines" explain preferred terminology and offer suggestions for appropriate ways to describe people with disabilities.
Understanding Gene Testing
This represents an effort by the National Cancer Institute and the National Center for Human Genome Research to provide basic information about gene testing and key genetic concepts. This booklet also provides answers to a number of frequently asked questions about the science, potential benefits, and potential risks of gene testing.
Genetic Counseling: Coping With the Human Impact of Genetic Disease
Genetic Consultation/Counseling: The Process
Describes what they do and how they do it.
Genetic Testing-Health Care Issues:An Interview with Dr. Neil Holzman
An excerpt from an interview with Dr. Neil Holzman that took place at the "Winding Your Way through DNA" symposium at the University of California San Francisco in 1992. Dr. Holzman is an M.D. and a health policy expert.
Genetic Conditions/ Rare Conditions: Support Groups & Information
Medical Genetics, University of Kansas Medical Center Professionals, educators, or individuals seeking information on genetic conditions or birth defects may find this list helpful; find additional information through the national and the international organizations listed below; or contact a genetic counselor or clinical geneticist.
OMIM Home Page--Online Mendelian Inheritance in Man
This database is a catalog of human genes and genetic disorders authored and edited by Dr. Victor A. McKusick and his colleagues at Johns Hopkins and elsewhere, and developed for the World Wide Web by NCBI, the National Center for Biotechnology Information. The database contains textual information, pictures, and reference information.
Mendelian Genetics, an interactive computer program which covers the main concepts of genetics
Genetic Counseling, March of Dimes Birth Defects Foundation
Newborn Screening
The Virtual Hospital™ uses the World-Wide Web (WWW) software technology to store, organize, and distribute multimedia textbooks including the Clinician's Handbook of Preventive Services.
DOE Primer on Molecular Genetics
This primer was prepared by Denise Casey (Human Genome Management Information System - Oak Ridge National Laboratory) for the1991-92 DOE Human Genome Program Report.
Home Page for Genetic Professionals
Information for genetic professionals at the University of Kansas Medical Center is updated regularly for genetic counselors, clinical geneticists, and medical geneticists with links to a variety of clinical, research and educational resources.
Genetics & Public Issues
The National Center for Genome Resources (NCGR) in Santa Fe, New Mexico is assembling educational and informational resources for the public, physicians and other professionals. This information is selected to help the public direct and make informed decisions about genetic information, technology and services. It is also selected to help industry and policymakers guide the application of genetic research and biotechnology. .
Geneticists & Ethicists Mentor Network,
Teachers and students can send questions to professionals in genetics, law, public policy, and ethics.

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