Blood Test Could Detect Cancer Risk Years Early in Lynch Syndrome Patients

Dr Eduardo Vilar-Sanchez, a physician-scientist at UT MD Anderson, has spent his career investigating how colorectal cancer originates—starting not with tumors, but with the normal colon lining that eventually transforms into precancerous lesions. To understand this process in its most extreme form, his team turned to Lynch syndrome, an inherited condition that can raise lifetime colorectal cancer risk as high as 80%, compared to about 5% in the general population.

Published in Nature Communications, the study asked a novel question: what has the immune system of a Lynch syndrome carrier learned from years of growing and removing precancerous polyps? Because Lynch syndrome tumors carry mutation-riddled proteins that appear foreign to the body, researchers hypothesized that the immune system has been "trained" by repeated exposure, even without a cancer diagnosis ever occurring.

By sequencing T-cell receptors in blood from 277 participants, the team found a distinct immune fingerprint that could reliably distinguish carriers from non-carriers. Even more notably, when researchers compared T-cell receptors from tumor and precancerous tissue to those in matched blood samples, they found substantial overlap: up to 41% of top tumor-associated T-cell receptors and 28% of those found in precancerous polyps were already detectable in blood.

This suggests the immune system mounts a measurable response even before a lesion becomes cancerous, raising the possibility of a blood-based biomarker for early cancer surveillance. Vilar-Sanchez envisions a future where routine blood draws could alert clinicians to emerging cancer risk or track how well experimental vaccines are boosting immune defenses. While clinical translation remains a challenge, he sees the ultimate goal clearly: helping patients "live longer, healthier, and cancer-free lives."

Read the full interview with Dr Vilar-Sanchez here.