PTEN and non-small cell lung carcinoma: Exosomal circFARSA (a circular RNA derived from the phenylalanyl-TRNA synthetase subunit alpha (FARSA) gene) generated from non-small-cell lung cancer (NSCLC) cells facilitates M2 polarization by enhancing PTEN ubiquitination and degradation, hence activating the PI3K/Akt pathway (119).