A liquid biopsy, when used to evaluate the health of organs from blood samples, primarily detects signs of cancerous tumors by analyzing circulating tumor cells (CTCs) or circulating tumor DNA (ctDNA) in the bloodstream.
How Liquid Biopsies Work
Liquid biopsies offer a less invasive alternative to traditional tissue biopsies. Instead of surgically removing a tissue sample, a simple blood draw is all that is required. Here's a breakdown of what they analyze:
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Circulating Tumor Cells (CTCs): These are cancer cells that have detached from the primary tumor and are circulating in the bloodstream. Detecting and analyzing CTCs can provide information about the tumor's characteristics, stage, and potential response to treatment.
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Circulating Tumor DNA (ctDNA): Tumor cells release DNA into the bloodstream. Analyzing this ctDNA can reveal genetic mutations and other abnormalities specific to the tumor. This information can be used to:
- Detect cancer early: ctDNA can be detected even before a tumor is visible on imaging scans.
- Monitor treatment response: Changes in ctDNA levels can indicate whether a treatment is working or if the cancer is progressing.
- Identify drug resistance: Mutations in ctDNA can reveal why a tumor is no longer responding to a particular therapy.
- Personalize treatment: ctDNA analysis can help select the most effective treatment based on the specific genetic profile of the tumor.
Advantages of Liquid Biopsies
- Less Invasive: Reduces the need for painful and risky surgical biopsies.
- Real-Time Monitoring: Can be performed repeatedly to track changes in the tumor over time, allowing for more timely adjustments to treatment.
- Accessibility: Easier to obtain samples, particularly for tumors that are difficult to reach with traditional biopsies.
- Comprehensive View: Can capture information about the entire tumor, including areas that may not be represented in a single tissue biopsy.
Example Application: Cancer Detection
As highlighted by the University of Chicago Medicine, liquid biopsies are increasingly used to detect signs of cancerous tumors using a simple blood test instead of an invasive needle procedure. This allows for earlier detection and monitoring of cancer progression and treatment response.
