Poor sleep may leave more than heavy eyelids and a rough morning. A large new analysis suggests it also leaves a measurable pattern among proteins in the blood, and that pattern is associated with higher risks for several cancers.
People with the healthiest overall sleep patterns had a 36% lower risk of liver cancer and a 14% lower risk of lung cancer than those with the poorest patterns.
A separate score built from 303 blood proteins was tied to lower risks for six cancers of the digestive system, but the findings show association, not proof that better sleep prevents cancer.
Five parts of healthy sleep
The study was led by Yangyang Liu of Memorial Sloan Kettering Cancer Center and used records from 472,105 eligible participants in the UK Biobank. Researchers scored five parts of sleep health, including sleep duration, chronotype, insomnia, snoring, and daytime sleepiness.
Chronotype simply means whether a person naturally tends to sleep and wake earlier or later. Scores of four or five were classified as healthy, two or three as intermediate, and zero or one as poor.
Why combine all five? A full night in bed does not always mean restorative sleep, especially when snoring, repeated waking, or that familiar afternoon slump enters the picture.
Researchers compared the scores with later cancer diagnoses and adjusted for demographic, lifestyle, medical, and family factors, which reduces some alternative explanations but cannot remove them all.
Blood proteins add a new clue
A subgroup of 52,920 people had measurements for 2,911 proteins in plasma, the liquid part of blood. Proteomics is the large-scale study of proteins, which act as messengers, enzymes, and building materials throughout the body.
The team repeatedly trained its models on 70% of the subgroup and tested them on the remaining 30%. The final overall sleep signature included 303 proteins and matched the sleep score only modestly in testing, although the result was highly unlikely to be due to chance.
Think of it as a molecular fingerprint rather than a diagnosis. “These findings highlight the potential of proteomic biomarkers in elucidating the relationship between sleep health and cancer risk,” the authors wrote.
The cancer links
Compared with poor sleep, a healthy score was associated with the lower cancer risks mentioned earlier. Those figures describe relative differences between groups, not the chance that any one person will develop cancer.
The protein score produced an even broader pattern. People in its highest third had 71% lower liver cancer risk, 54% lower stomach cancer risk, and 53% lower pancreatic cancer risk than those in its lowest third.
Researchers also reported 54% lower gallbladder cancer risk, 35% lower esophageal cancer risk, and 28% lower colorectal cancer risk. The size of those associations is notable, but it would be a mistake to read them as guaranteed benefits from changing bedtime habits.
What the proteins may mean
Earlier research on sleep-related proteins found that many were connected to inflammation, immune activity, and the body’s complement system, a defense network in the blood. That does not prove these same pathways caused the cancer associations here, but it gives scientists a map of where to look next.
Proteins can reflect many influences at once, including sleep, weight, smoking, existing disease, medication, and age. The new score may therefore capture a wider health pattern rather than a clean biological effect of sleep alone.
For now, this is not a blood test that a doctor can order to calculate a patient’s sleep-related cancer risk. It was developed and checked within one large research resource, so outside validation and studies that measure sleep repeatedly would be needed before clinical use.
What sleepers should take from it
The practical message is not that one bad night causes cancer. Cancer develops through many interacting factors, and an observational study cannot show that sleep was the direct cause of the differences.
Still, the study strengthens the case for treating sleep as a whole health pattern rather than counting hours alone. Persistent insomnia is worth discussing with a health professional, while frequent loud snoring or heavy daytime sleepiness can be signs of sleep apnea.
At the end of the day, the study’s most original contribution is not another reminder to sleep more. It is the suggestion that sleep health may leave a biological trail in blood, one that could eventually help researchers explain why cancer risk differs between groups.
The official study abstract was presented at Digestive Disease Week 2026 in Chicago and published in Gastroenterology.
