PROVIDING THE LATEST INFORMATION FOR PATIENTS & CAREGIVERS Understanding Genetics Revised 2020 Support for this publication provided by A six-word narrative about living with blood cancer from patients in our LLS Community Stay strong and keep moving forward. Find the positive in every day. Be your own best patient advocate. Changed my life for the better. Accept, learn and focus on present. Learning to live a different life. Sudden and life changing—be positive. Waiting, worrying, anxiousness/ happy I’m alive! Embrace a new normal each day. 5 years, 41 infusions, constant fatigue. Patience, positive attitude, hope and faith. Test to test, I will survive! Treatment, fatigue, treatment, fatigue and survival. Love life, live better every day. I don’t look back only forward. So far, so good, live life. Meditation, mindfulness, wellness, faith, nutrition and optimism. Finding the joy while living with uncertainty. Watch, wait, treat, regroup, rest, re-energize. 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Members will find: • Thousands of patients and caregivers sharing experiences and information, with support from knowledgeable staff • Accurate and cutting-edge disease updates • The opportunity to participate in surveys that will help improve care Inside This Booklet 2 Introduction 4 Cells 4 Chromosomes 6 DNA (deoxyribonucleic acid) 7 Genes 7 Mutations 15 The Genetics of Cancer 15 Types of Testing for Mutations in Cancer Cells 17 Precision Medicine 18 Research and Clinical Trials 19 Resources and Information 22 Other Resources 23 Health Terms Acknowledgement The Leukemia & Lymphoma Society (LLS) appreciates the review of this material by Patrick T. Fueger, MS, PhD Associate Professor, Department of Molecular & Cellular Endocrinology Director, Comprehensive Metabolic Phenotyping Core Beckman Research Institute City of Hope Duarte, CA This publication is designed to provide accurate and authoritative information about the subject matter covered. It is distributed as a public service by LLS, with the understanding that LLS is not engaged in rendering medical or other professional services. Introduction Cancer is a disease that is caused by abnormal changes (mutations) to the genetic material inside of cells. This genetic material is called DNA (deoxyribonucleic acid). When cells divide to create new cells, the DNA is passed to the new cells. Therefore, mutated DNA may cause the new cells to develop into cancer cells. Cancer cells behave differently than normal cells. They multiply uncontrollably even though they are not needed in the body, and evade the immune system. DNA damage and mutations happen more commonly than one might think but the immune system usually identifies these abnormal cells and eliminates them. Some of these abnormal cells that avoid immune detection go on to become cancerous cells. These cancer cells can spread to surrounding areas and form tumors. The cancer cells can build up in the blood, the bone marrow (the spongelike tissue in the center of most bones), the lymph nodes and other areas of the body. Genetics and Genomics. Each person’s cancer has a unique combination of genetic mutations. Genetic materials are examined in two different, but complementary, fields of study, namely genetics and genomics. “Genetics” is the study of genes and their roles in inheritance—the ways in which traits or conditions are passed down from one generation to the next. “Genomics” is the study of the complete set of DNA of a person’s genome; the genome is made up of all of a person’s genes. Genomics also examines how the genes interact with each other and how, or if, they are affected by environmental factors. Researchers are learning that the genetic changes that occur in one person’s cancer may not occur in other people who have the same type of cancer. Specific information about a person’s own genes and/or proteins is used to prevent, diagnose, or treat cancer in an approach to a type of care known as “precision medicine.” Genetic and genomic testing provides doctors with the individualized information (based on specific genetic changes and the genomic makeup of abnormalities within the cancer tissue) that they need to develop specific targeted treatments for their patients. { Genetic testing: These tests examine changes in an individual gene and/or set of genes that may account for the likelihood of a particular disease process; however, a test may not pick up every change in a gene. This type of information is useful if a particular drug is known to work for certain gene/protein variants. It allows for targeted therapies (for example, Tibsovo® [ivosidenib], which is approved for treatment of acute myeloid leukemia in patients who have an IDH1 gene mutation). 2 I 800.955.4572 I www.LLS.org { Genomic testing: These tests assess an individual’s genome (all of a person’s genes, rather than a specific gene or set of genes). The scope of genomic testing includes gene alterations (mutations) and/or harmful changes in the genetic code—however they are caused. Researchers hope that, one day, testing cancer cells for mutations this way will help doctors match each patient with the most effective treatment for his or her disease. Cells, Chromosomes, and DNA Human Cell Nucleus DNA Chromosome A T Base © Fran Milner 2020 pairs C G Highlights. In this booklet you will learn that { The human body is made up of trillions of cells. { In almost every cell, there is a nucleus that contains your genome (all of your genetic material), which is essentially a blueprint for your body to develop and grow. { In the nucleus of most cells, your genetic material is packaged into thread like structures called “chromosomes.” { Chromosomes are made of DNA (deoxyribonucleic acid) that is wrapped around specialized proteins called “histones.” { DNA is the hereditary material that passes from one generation to the next. Nearly every cell in your body has the same DNA. { Cancer is a disease that is caused by abnormal changes (mutations) to the genetic material inside of cells. Understanding Genetics I 3 { Each person’s cancer has a unique combination of genetic mutations. Precision medicine is an important approach to patient care that allows doctors to select treatments that are tailored to specific genetic changes of each person’s cancer. Feedback. Visit www.LLS.org/PublicationFeedback to give suggestions about this booklet. Cells Cells are considered the basic units of life. The human body is made up of trillions of cells that carry out essential functions allowing the body to survive. Each type of cell plays a specific role in the body. For example, red blood cells carry oxygen throughout your body; nerve cells send electrical messages that create thoughts and movement; and heart cells contract to pump blood. Cells also make products that your body needs such as sweat, saliva, and hormones. In almost every cell, there is a nucleus that contains your genome (all of your genetic material). Your genome is essentially a blueprint for your body to develop and grow. Chromosomes In the nucleus of most cells, your genetic material is packaged into threadlike structures called “chromosomes.” Human cells normally contain 23 pairs of chromosomes, for a total of 46 chromosomes. Chromosomes are passed from the parents to a child. You inherit 23 chromosomes from your mother’s egg cell, and you inherit the other 23 chromosomes from your father’s sperm cell. Under the microscope, you can see that chromosomes come in different lengths and striping patterns. The first 22 of these pairs are called “autosomes,” and they are the same in males and females. The 23rd pair is the sex chromosomes; female and male sex chromosomes are different. Females have two copies of the X chromosome, whereas males have one X chromosome and one Y chromosome. Somewhere between one-third and two-thirds of the way down the chromosome is the centromere, p arm a narrow region that divides the chromosome into Centromere two sections, or “arms.” The short arm of the chromosome is called the “p arm,” and the long arm q arm of the chromosome is called the “q arm.” Geneticists use the names of the arms to describe the position of a specific section of the chromosome. For example, 13q describes the long arm of chromosome 13, while 17p describes the short arm of chromosome 17. © Fran Milner 2020 4 I 800.955.4572 I www.LLS.org This image of normal human chromosomes lined up in pairs is called a “karyotype.” KaryotypeKaryotypeKaryotypeKaryotypeKaryotypeKaryotype FromFromFrom FrommotherFromFrom mother mother mothermother mother p arm (egg)(egg)(egg)(egg)(egg)(egg) p armp armppp p arm armarm arm CentromereCentromereCentromereCentromereCentromereCentromere FromFromFrom FromfatherFromFrom father father father father father (sperm)(sperm)(sperm)(sperm)(sperm)(sperm) q armq armqqq q arm armarm arm 1 1 1111 2 2 2222 3 3 3333 4 4 4444 5 5 5555 6 6 6666 7 7 7777 8 8 8888 9 9 9999 10 1010101010 11 11 11111111 12 1212121212 13 13 13131313 14 14 14141414 15 1515151515 16 1616161616 17 17 17171717 18 1818181818 19 1919191919 202020202020 21 2121212121 222222222222 XXXX (Female)XXXX XX(Female)XX (Female) (Female)(Female) (Female)XYXY (Male)XYXY XY(XYMale) ( (Male)(Male) Male)(Male) © Fran Milner 2020 © Fran© FranMilner©©© Fran ©Fran MilnerFran 2020Fran Milner Milner Milner 2020Milner 2020 2020 2020 2020 Understanding Genetics I 5 DNA (deoxyribonucleic acid) Chromosomes are made of DNA.