A recent circRNA microarray analysis-based study revealed 120 differentially expressed circRNAs in the lungs of silicosis mice (Figure S2), among which circHECTD1 is of particular interest because its host gene, HECTD1, a candidate E3 ubiquitin ligase, may be involved in SiO2-induced fibrosis by inducing ubiquitination32. Here, HECTD1 is linked to silicosis.