Oncogenes <i>WNT1</i>, <i>WNT2</i>, <i>c-MYC</i> and <i>NOTCH1</i> are specifically overexpressed in SP of human lung adenocarcinoma cell line A549.

<p><b>A</b>. SP cells in A549 were detected and separated by FACS using the Hoechst33342 dye efflux method (left) and verified by their failure to efflux this dye after incubation with FTC, a specific inhibitor of multidrug transporter-ABCG2 (right). This figure represents 1 of 3 experiments. The mRNA expression levels of oncogenes and stem cell genes were compared between the SP and NSP cells by using semi-quantitive RT-PCR, real-time RT-PCR in <b>B</b> and <b>C</b> separately, n = 3. <b>D</b>. Western blotting results of WNT1, WNT2, NOTCH1, c-MYC and SOX2 proteins in SP and NSP of A549 cells.