By analyzing the expression levels of circRNA CDR1as, miR-641 and HOXA9 in the above cells (Fig. 1c–g), we surprisingly found that circRNA CDR1as (Fig. 1c) and HOXA9 mRNA (Fig. 1e) were upregulated, but miR-641 (Fig. 1d) was downregulated in DDP-resistant NSCLC cells compared to the DDP-sensitive NSCLC cells. Here, HOXA9 is linked to non-small cell lung carcinoma.