IGF1R and myasthenia gravis: MiR-497 has been validated to inhibit IGF1R expression via targeting IGF1R mRNA in human colorectal cancer [48], which strengthens our speculation that the other 4 miRNAs inhibit IGF1R. Moreover, one recent miRNA microarray analysis has shown a decreased level of miR-15a, miR-15b and miR-16 in MG patients [6], which might be the cause of the increased IGF1R in the MG patients' thymus.