SCGB3A2 and breast cancer: We found that both serous and club cells express high levels of the secretoglobin Scgb3a2, but that club cells were unique in their expression of another secretoglobin family member, Scgb1a1. Furthermore, serous cells of the PR8-exposed lung include a subset that harbor transcripts for BC marker genes including Trp63, Krt14, and Krt5, present at variable levels among all post-exposure recovery time points but absent in airways of naïve mice (Fig. 1G).