PROBLEM

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Many people still have residual cancer after completing cancer treatment. The 5-year survival rate very poor for those people because the cancer have time to spread. Clinical trials have shown  improve the survival of these patients by providing additional treatment to those who need it, using a new approach call a liquid biopsy. A liquid biopsy is a blood draw which looks molecular markers associated with cancer cells. However, the current liquid biopsy tests are not good enough to become the standard of care and enable treatment. Our goal is to enable better cancer treatment through improving cancer diagnostics.

• High Sensitivity: The earlier cancer is diagnosed, the better the outcome. Ideally, a single copy of cancer DNA could be detected.
• High Specificity: Cancer treatment is toxic, so there cannot be any false positives.
• Standardization: The test needs to have quality control to ensure the performance.
• Cost-Effective: Frequent testing is needed to diagnose residual cancer early.

Cancer DNA is rare, relative to normal DNA, in your blood (e.g. 1 copy of cancer DNA and 20,000 copies of normal DNA). In order to find the cancer DNA, a test may have to sequence 100,000 copies of DNA, because of probability. Additionally, the cancer DNA is very similar to normal DNA. This is a problem because the scientific method for sequencing DNA is to "infer" the sequence, instead of "observing" the sequence. The DNA sequence is "inferred" using Watson and Crick base pairing. An "C" pairs with a "G", so if the fluorescence signal from a "C" is observed, then the target DNA strand is "inferred" to be a "G" at that position. However, sometimes a "C" will bind to an "T" or an "A", because base pairing is imperfect. This is the foundational error that limits the accuracy (sensitivity and specificity) of all cancer diagnostics that sequence DNA. Unfortunately, this error rate of current DNA sequencing methods is 0.1 - 0.5%, which is higher than the target sensitivity of a cancer tests (<0.01%).

The SentryDx solution addresses these two major limitations:

1. Large amount of DNA sequencing needed to find low frequency cancer DNA
2. High error rate of sequencing by synthesis.