The broader impact/commercial potential of this Small Business Innovation Research (SBIR) Phase I project is to improve the diagnosis of residual cancer cells, after treatment of cancer patients. The test will be conducted early and accurately using a simple blood draw. Twenty percent of cancer patients will experience cancer recurrence. Unfortunately, cancer recurrence is not diagnosed until years after initial treatment when the cancer has often metastasized, resulting in poor patient outcomes. As a result, 7% of cancer patients suffer from debilitating fear of cancer recurrence. Early and accurate diagnosing of residual cancer cells will improve the outcome for the 20% of cancer patients who experience recurrence. Additionally, it will help the 7% of cancer patients who suffer from debilitating fear of cancer recurrence. Overall, the costs of treating cancer will be lowered by diagnosing cancer earlier. This Small Business Innovation Research (SBIR) Phase I project seeks to develop a highly accurate diagnostic test for residual cancer from a blood draw. DNA (deoxyribonucleic acid) from cancer cells circulates through the blood stream. This cancer can be detected because of mutations in the DNA of cancer cells. However, cancer DNA is rare compared to normal DNA, which makes diagnosing cancer from a blood draw difficult. Proof-of-concept data has shown that accuracy can be greatly improved through the enrichment of cancer DNA from a sample. After the sample is collected, the DNA goes through rounds of duplication, except a blocker is added to prevent normal DNA from duplicating. Through this process the cancer DNA becomes a larger percentage of the overall DNA in the sample and can be more accurately detected. This project will develop a collection of tests for accurately diagnosing residual colorectal cancer. The key tasks of this project are: 1) demonstrate the clinical robustness of the optimized test method, 2) develop additional tests to cover most colorectal cancers, and 3) demonstrate the sensitivity and specificity of the test methods. This project will lead to earlier and more accurately diagnosed cancer recurrence.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.