TOP2A and neoplasm: Cell type annotation based on marker gene expression [9] showed that the lung organoids contained diverse epithelial cell types and states in the human lung, including cycling cells (MKI67, TOP2A), basal cells (TP63, NGFR), suprabasal cells (KRT6A, SERPINB4), club cells (SCGB1A1, TFF3), goblet cells (MUC5AC, SPDEF), ciliated cells (PIFO, CDHR3), and tumor cells (Figure 3B–D).