Principal component analysis-based comparison of airway basal cells to other human tissues and cells.

Compared tissues and cell types were all of human origin and included: basal cells (human airway basal cells, red; n = 5); differentiated epithelium (complete large airway epithelium obtained by brushing, green; n = 12); ALI-d0 (basal cells cultured on ALI until confluent, ∼2 days after plating (see Methods), grey; n = 3); ALI-d28 (the same airway basal cells after 28 days of differentiation in air-liquid interface, yellow; n = 3); breast stem cells (from Gene Expression Omnibus GSE15192: CD44+ CD24− stem-like fraction of MCF-10A immortalized breast epithelial cells, dark blue; n = 4), basal-like breast cancer (GSE3744: orange; n = 5); keratinocytes (GSE7216: primary neonatal foreskin epidermal keratinocytes, pink; n = 3); cervical cancer (GSE5993: p63-overexpressing cervical cancer cell line ME180; light blue; n = 3); and fibroblasts (GSE17032: human skin and lung fibroblasts, purple; n = 20). A. Analysis based on the entire transcriptome. B. Analysis based on the 1,161 genes of basal cell signature.