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Cancer Genomics

What is Cancer Genomics?


What does cancer genomics mean for a patient?

According to the NIH Publication No. 10-7556 “Cancer Genomics”, one person dies from cancer every minute in the United States. It is estimated that 1,500 people die from cancer each day. And the number of people dying per day in the future is expected to increase with the aging population. To understand, control and conquer cancer, medical researchers have to understand this disease. Since cancer starts in our DNA, many medical researchers are working hard to find cures for the many faces of cancer.

DNA or deoxyribonucleic acid carries instructions that tell cells what to do. Mistakes found in these instructions may cause the cells not to function normally. Accumulated mistakes or changes found in DNA responsible for the instructions are called mutations. Some of these mutations can be inherited, but most are acquired throughout life. Acquired mutations must be caused by environmental factors, such chemicals, or from lifestyle choices, for example, caused by smocking.

What is a genome?

The complete set of instructions in the DNA is called a genome. The term “genome” refers to the complete genetic material of an organism. In humans, it is called the “human genome.” In most cells, the genome is physically packaged into two sets of chromosomes. One set originates from the mother and one from the father. Six billion individual DNA letters or nucleotide monomers make up the human chromosomes.

The alphabet of the genome consists of four (4) letters: A, C, G, and T.  Small changes in the arrangement of these letters within the genome can result in changes of genetic instructions for a cell. Genes are parts of a genome that carry instructions to make molecules that do most work in the cell. Other parts of the genome can switch genes on and off. Depending on the function of a cell or tissue type, different genes are used by the cell. Liver cells use a set of genes needed for liver proteins whereas muscle cells use genes needed to make muscle proteins. 

What is a gene?

The term ‘gene’ refers to the functional and physical unit of heredity. This unit is passed on from parents to their offsprings or children. Most genes contain the instructions to make a specific protein. Germline DNA contains inherited mutations.

What is germline DNA?

Germline DNA is found in germ cells. Eggs and sperm cells are germline cells that join to form an embryo. This type of DNA is the source for all other cells in the body and is also called constitutional DNA.

What is somatic DNA?

Somatic DNA is the DNA found in body cells but not in the germ cells. Therefore, somatic mutations are alterations or changes in the DNA that occur after conception. Somatic mutations are not present in germ line DNA and are therefore not passed on to children. Many somatic mutations can cause diseases such as cancer. However, not all somatic mutations cause diseases.

What are the effects of changes or mutation in DNA?

Changes or mutation in DNA can cause cells to make the wrong amount of one protein or change the shape of a protein so that it does no longer work as it should. Because proteins control the behavior of cells, mutations may lead to health problems. In cancer, these changes can cause cells to grow out of control. As a result, these cells can damage the surrounding tissues.

What is the Cancer Genome Atlas?

The Cancer Genome Atlas (TCGA) Data Portal provides a platform for researchers to search, download and analyze data sets. These data sets were generated by TCGA. The National Cancer Institute at the National Institute of Health (NCI/) established the atlas. The goal of the TCGA is to help researchers understand what turns a normal cell into a cancer cell.

The comparison of DNA from normal and cancer tissue has already shown that

•    Certain areas of the genome are commonly affected in several types of cancer. Affected genes are often genes that control signaling pathways that cause cells to divide and survive when they normally would die.

•    Specific changes or cell signatures often also called biomarkers allow researchers to tell what type of cancer is present. These signatures may help medical doctors to identify specific cancer types. Medical researchers already know that different types of cancer respond differently to various treatments or have a different prognosis. 


Reference

http://cancergenome.nih.gov/