To further elucidate the underlying mechanism of miR-140–5p/IGF1R in the malignant phenotype of TGCT, the authors separately transfected mimic-NC, miR-140–5p mimic, and co-transfected miR-140–5p mimic with pcDNA3.1-IGF1R into cells. This evidence concerns the gene IGF1R and testicular germ cell tumor.