TFF3 and breast cancer: For both TFF3 (goblet cell marker) and CC10 (Clara cell marker), low levels of expression at ALI day 0 were detected; however, like primary BC, a significant increase in expression was observed at ALI day 28 (TFF3, p < 0.001; CC10, p < 0.05), demonstrating BCi-NS1.1 cells can differentiate into both goblet and Clara cells.