However, PB-MCT do not fully recapitulate the in vivo MCT phenotype, underlining that the ultimate phenotype of inflammation-driven MCTs is likely directed by the combined effect of both microenvironment and inflammation-associated signals such as IL-4, previously shown to similarly upregulate a portion of nasal polyp MCT-associated transcripts (3). This evidence concerns the gene IL4 and Nasal polyposis.