Screening and treating early breast lesions (DCIS) hasn’t done much to lower breast cancer deaths, a sign that some tumors are already headed down a dangerous path before doctors can catch them. This dataset captures one such fork in the road. Using a cell-tracking technique, researchers followed tumor lineages in mice with different HER2 gene variants and found that one variant, p95-HER2, produces fast-growing, invasive tumors that skip the usual precancerous stage entirely. To capture this, the team sequenced RNA from individual cells across 12 HER2-positive mouse tumors. The results map how a tumor’s genetics shape its earliest path, and could help spot dangerous cancers that current screening misses.
