How methylation works

Methylation is a biological process active in all living cells that determines which sections of the DNA to turn on or off. In cancerous cells, methylation becomes abnormal. The human body continually releases DNA fragments from dying cells into our blood. The methylation patterns of these fragments indicate the type of cell they originated from, including cancer cells.

Although abnormal methylation is a common feature of all cancers, the rate at which different cells in the body shed DNA is inherently different, and also varies by the stage of the cancer.1

Consequently, the Galleri test is more sensitive for certain cancers than others, and for certain stages. Even so, it can detect a signal shared by over 50 types of cancer, and many at early stages, as aggressive and invasive cancers appear to shed more DNA in earlier stages than slow-growing cancers that are less likely to cause death.1

The Galleri test does not detect a signal for all cancers and not all cancers can be detected in the blood. False positive and false negative results do occur.

Following extensive clinical research, GRAIL believes methylation is the most promising approach to detecting a cancer signal and identifying the tissue type or organ associated with the cancer signal.

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Learn more about Galleri

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    Important safety information

    The Galleri test is recommended for use in adults with an elevated risk for cancer, such as those aged 50 or older. The Galleri test does not detect all cancers and should be used in addition to routine cancer screening tests recommended by a healthcare provider. Galleri is intended to detect cancer signals and predict where in the body the cancer signal is located. Use of Galleri is not recommended in individuals who are pregnant, 21 years old or younger, or undergoing active cancer treatment.

    Results should be interpreted by a healthcare provider in the context of medical history, clinical signs and symptoms. A test result of “Cancer Signal Not Detected” does not rule out cancer. A test result of “Cancer Signal Detected” requires confirmatory diagnostic evaluation by medically established procedures (e.g. imaging) to confirm cancer.

    If cancer is not confirmed with further testing, it could mean that cancer is not present or testing was insufficient to detect cancer, including due to the cancer being located in a different part of the body. False-positive (a cancer signal detected when cancer is not present) and false-negative (a cancer signal not detected when cancer is present) test results do occur. Rx only.

    Laboratory/test information

    GRAIL’s clinical laboratory is certified under the Clinical Laboratory Improvement Amendments of 1988 (CLIA) and accredited by the College of American Pathologists (CAP). The Galleri test was developed, and its performance characteristics were determined by GRAIL. The Galleri test has not been cleared or approved by the U.S. Food and Drug Administration. GRAIL’s clinical laboratory is regulated under CLIA to perform high-complexity testing. The Galleri test is intended for clinical purposes.

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    1. Klein EA, et al. Ann Oncol. 2021;32(9):1167-1177. doi: 10.1016/j.annonc.2021.05.806.