Correspondingly, POU2AF2 has been shown to interact with POU2F3, a master transcriptional regulator of tuft cells,8 in small cell lung cancer, characterised by high POU2F3 expression (SCLC-P).9 10 These studies suggest that tuft cell function may be influenced by genetic variation at 11q23.1; however, germline genetic regulation of these genes, and their relevance to human colonic epithelium and CRC risk, remain to be determined. This evidence concerns the gene POU2F3 and small cell lung carcinoma.