Members of the international Trans-Omics for Precision Medicine (TOPMed) program present a compendium of mutational processes in the human germline in this week's Science. In the report, the multi-institute team of investigators use variations in mutation rate along the genome to model germline mutagenesis using a sequencing dataset from the program. Their analysis reveals nine processes that explain the variation in mutation properties between loci, and the group provides biological interpretations for seven of them.
By analyzing gastroesophageal tissue from healthy individuals and patients with Barrett's esophagus, a team led by scientists from the University of Cambridge have uncovered the molecular origins of this metaplastic, and frequently oncogenic, condition. As reported in Science this week, the researchers harvested tissues from across the gastroesophageal junction from healthy and diseased donors, which they examined using a variety of techniques including combination of single-cell transcriptomic profiling, in silico lineage tracing from methylation, and open chromatin and somatic mutation analyses. They find that Barrett's esophagus originates from gastric cardia through transcriptional programs driven by the oncogene c-MYC and the transcription factor HNF4A. "Furthermore, our data indicate that esophageal adenocarcinoma likely arises from undifferentiated Barrett's esophagus cell types even in the absence of a pathologically identifiable metaplastic precursor, illuminating early detection strategies," they write.