IRAK1 and synovial sarcoma: In addition, Zilahi et al. (2012) found that miR-146a/b expression was upregulated in PBMCs from SS patients compared to that in healthy controls, while IL-1 receptor-associated kinase 1 (IRAK1) expression was downregulated, implying the existence of transcriptional repression of IRAK1 by miR-146a in SS patients.