DNA changes in certain blood cancers may signal progression to acute myeloid leukemia or myelofibrosis years before routine blood tests detect them.
https://www.foxnews.com/health/cancer-warning-signs-may-appear-dna-years-before-blood-tests-detect-trouble
https://www.foxnews.com/health/cancer-warning-signs-may-appear-dna-years-before-blood-tests-detect-trouble