Minimal residual disease: What is it and why is it important?

The takeaway: What is MRD in cancer? Minimal residual disease refers to the small number of leukemic cells that remain in a person during or after treatment for cancer. New advancements are helping IDT expand access to and expedite turnaround time for minimal residual disease research solutions.

The quest to help more people live cancer-free is leading researchers to focus on the presence of circulating tumor DNA (ctDNA), which can be a reliable indicator of minimal residual disease—or the small number of cancer cells that remain in a person during or after treatment for cancer.

This emerging area of study is an important one for IDT, which recently launched a complete MRD workflow that includes the xGen™ MRD Hybridization Panel and xGen cfDNA & FFPE DNA Library Preparation Kit, which are now available as a bundled solution for researchers who want to accelerate key MRD research discoveries.

What is minimal residual disease?

A person’s cancer is considered to be cured when the cancer cells are totally removed from their body. While there are treatments to remove cancer cells, the catch is that it is important to not damage too many healthy cells in the process. Minimal residual disease is a term that describes a small number of cancer cells left behind during or after cancer treatment. Here is where an MRD cancer test comes in. Formerly difficult to detect, minimal residual disease can be found using extremely sensitive lab methods that can identify a single cancer cell among a huge number of normal cells. Being able to identify this leftover cancer can provide clues as to how well a treatment is working or if a cancer has come back, and it can be used to make a more personalized prognosis. Researchers today are working hard to develop blood tests that can detect MRD—an important step for those seeking to lower their chances of cancer recurrence.

What is MRD testing?

MRD cancer testing can be used to find evidence of a very small number of cancer cells. MRD testing can be used to catch relapses, identify people who are at risk for relapse, determine if a cancer treatment was effective, and let care teams know when they can change, resume, or stop treating a person’s cancer.

What cancers can MRD be used on?

MRD tests are primarily used to detect blood cancers such as multiple myeloma and leukemia. The latest generation of minimal residual disease tests include those for colorectal cancer, solid tumors such as breast and ovarian cancer, and lung cancer.

How does minimal residual disease testing work?

Minimal residual disease tests can take a variety of forms, including testing that looks for circulating tumor DNA, or ctDNA, which is a small fragment of DNA that cancer cells release and wind up in the blood stream; this test can work through next generation sequencing, which looks for patterns of DNA that match the DNA of cancer cells, or polymerase chain reaction, which looks for DNA that contains genetic patterns that are known to identify cancer.

Why is minimal residual disease research so important?

The ability to track the presence of cancer cells is highly important to researchers. Tracking these cells faster, earlier, and at increasingly lower levels is the goal of current MRD research. Research into the development of library preparation methods that maximize the conversion of tiny cfDNA samples, combined with tumor-specific targeted deep sequencing methods, are now underway to find the lowest levels of cancer that can be identified while still being accurate. Some methods allow for very low detection of tumor plasma cells using next generation sequencing (NGS). NGS panels are also being developed to allow for MRD testing of even more cancers, and some can be customized to take into account the huge variety of mutations found in different cancers.

Stocked panels such as the xGen™ Acute Myeloid Leukemia (AML) Cancer Hybridization Panel are being used in research. A stocked panel like this, or a custom panel speciifc to recurrently mutated genes in other cancer types, can be utilized to identify variants which form a patient-specific tumor signature. Once done, a custom capture panel can be designed that is specific to the tumor DNA that is being studied. The xGen MRD Hyb Panel and xGen cfDNA & FFPE DNA Library Preparation Kit work for these uses.

What is the future of MRD research?

In recent years, notable progress has been made in the scientific understanding of and treatment for various cancers. Molecular methods to identify minimal residual disease can improve treatment methods and speed, potentially resulting in improved treatments. While MRD is so far an in-progress cancer identification method, it has strengths that make it worthy of continued research.

*RUO—For research use only. Not for use in diagnostic procedures. Unless otherwise agreed to in writing, IDT does not intend for these products to be used in clinical applications and does not warrant their fitness or suitability for any clinical diagnostic use. Purchaser is solely responsible for all decisions regarding the use of these products and any associated regulatory or legal obligations. Doc ID RUO23-1849_0011