Blood, cell-free DNA and tRNA carry disease signals at different scales
An Alzheimer's blood test received regulatory clearance, while a nucleosome pattern for breast-cancer recurrence and tRNA changes in infectious Chagas parasites remained research findings.
Science··Evening
An Alzheimer's blood test will aid clinical evaluation
The US Food and Drug Administration cleared C2N Diagnostics' PrecivityAD2 blood test for marketing. It measures plasma amyloid-beta and tau ratios to aid evaluation of amyloid pathology in adults whose cognitive symptoms are consistent with early Alzheimer's disease. The company reports agreement above 90 per cent with cerebrospinal-fluid and amyloid-PET reference tests. Its probability score must be interpreted with clinical history and other information; it is not a standalone diagnosis and does not measure disease severity or predict an individual's progression.[1]
The Chagas parasite changes its tRNA map in the infectious stage
Silva and colleagues mapped 170 tRNA modification sites that differ between the non-infectious and infectious forms of Trypanosoma cruzi. Combining RNA sequencing, mass spectrometry, bioinformatics and CRISPR-based gene editing, the team identified chemical changes that may adjust protein production as the parasite changes stage. The findings define molecular machinery that could later be investigated for intervention targets. The study does not present a drug candidate and should not be read as a clinical treatment result for Chagas disease.[2]
A nucleosome pattern distinguished breast-cancer recurrence
A Kumamoto University team examined circulating cell-free DNA from 105 primary and 45 recurrent or metastatic breast-cancer samples. A score based on DNA packaging around nucleosomes at RERE and SYNPO2, rather than mutations, distinguished primary from recurrent disease with an area under the ROC curve of 0.826. The authors describe the dataset as relatively limited and retrospective. Without larger prospective studies, the finding does not replace existing follow-up imaging.[3]
