Remarkably, an average of 73.9% (± 8.0%) of EdU-labeled fibroblasts were labeled with tdTomato (Figure 1B), closely mirroring the 78.1% labeling efficiency of alveolar fibroblasts by Scube2-CreER in saline controls (Figure 1C) (22), suggesting that the vast majority of fibroblasts incorporating EdU in each fibrosis model were derived from alveolar fibroblasts. Here, SCUBE2 is linked to fibrosis.