Mechanistically, Ni exposure induced miR-21 expression via activating the EGFR/NF-κB signaling pathway; up-regulated miR-21, in turn, suppressed the expression of two miR-21 target genes, SPRY2 and reversion-inducing cysteine-rich protein with kazal motifs (RECK), and promoted invasiveness of lung cancer cells [146]. This evidence concerns the gene EGFR and lung cancer.