RAC1 and non-small cell lung carcinoma: SOX2OT contributes to bone metastasis of NSCLC by regulating the TGF‐β/pTHrP/RANKL signalling pathway in osteoclasts through miR‐194‐5p/RAC1 signalling while MLETA1 promotes metastasis through modulating miR‐186‐5p/EGFR and miR‐497‐5p/IGF1R pathways in small cell lung cancers.224