hsa-mir-663b: Hsa-mir-663b is a microRNA that has been selected to confirm the impact of IL21 on gene expression [PMC4549109]. In a study, it was found that IL21 downregulates several miRNAs, including hsa-miR-7-2-3p, hsa-miR-7-5p, hsa-miR-1179, hsa-miR-130b-5p, hsa-miR-144-5p, and hsa-miR-328-3p [PMC6458921]. Conversely, IL21 upregulates miRNAs such as hsa-miR-767-5p and hsa-mir663b [PMC6458921]. Hsa-mir663b is a human microRNA that has been shown to be upregulated in response to IL21 [PMC6458921]. It is important to note that the specific role of this microRNA in gene expression modulation is not mentioned in the given context. However, it can be inferred that its upregulation may have an impact on gene expression patterns. In conclusion, the selection of hsa-mir663b as a target for investigation suggests its potential involvement in the modulation of gene expression by IL21. Further research is needed to elucidate the specific mechanisms and targets of this microRNA in order to fully understand its role in gene regulation.