The human body is made up of trillions of individual cells. Each cell contains the complete DNA code needed to make every part of the human body. Genes are long strands of DNA that give each person their individual characteristics.

Sometimes, cancer can be caused by errors in specific genes like BRCA1 and BRCA2 that have been linked to breast and ovarian cancer or EGFR that has been linked to lung and colon cancer.

This large amount of DNA can fit into a cell because it is tightly packaged into unique chromosome structures. Each cell has 23 pairs of chromosomes, making 46 chromosomes in total. Thousands of genes are located in each chromosome, and this packaging helps ensure that the DNA is kept intact during cell replication and division.

When a cell divides, it first duplicates all 46 chromosomes so they can be split evenly into the two daughter cells. Each daughter cell will receive two copies of every chromosome. A system of checkpoints throughout cell division normally regulates this critical process. If something goes wrong during cell division and chromosomes are not divided evenly, there will be an abnormal number of chromosomes in each daughter cell, this is called aneuploidy. Aneuploidy usually refers to the addition or deletion of one full chromosome.

WHAT CAUSES ANEUPLOIDY

Sometimes, aneuploidy happens during fetal development resulting in chromosomal anomalies. Other times, aneuploidy happens spontaneously when cells erroneously copy their genetic code as they prepare to divide or when chromosomes are incorrectly separated intro daughter cells. In cancer cells, the checkpoints that regulate errors in cell division are sometimes broken, and mistakes can happen that produce daughter cells with too many or too few chromosomes.

Another type of error that can occur in cancer is called partial aneuploidy. Partial aneuploidy happens when a chromosome breaks and only parts of the chromosome are gained or lost following cell division.

HOW ANEUPLOIDY IS DIAGNOSED

Aneuploidy is a type of genomic instability that is one of the hallmarks of cancer. The degree of aneuploidy in tumor cells can be used to predict cancer progression and outcomes. It can also be used to direct the treatment of certain cancer types with a potential for targeted therapy.

At Caris, we partner with patients and oncologists to provide the most comprehensive testing available. Understanding your cancer at a molecular level and detecting genomic instabilities, like aneuploidy, will assist your doctor in making the most informed decisions regarding your cancer treatment.