FGL1 and lung adenocarcinoma: However, FGL1 levels are widely believed to be associated with poor patient prognosis, especially as recent study has shown that FGL1 levels in circulating EVs from patients with lung adenocarcinoma more sensitively reflect tumor progression and correlate with responsiveness to anti-PD-1 therapy than free FGL1 in plasma126, suggesting a complementary immunosuppressive function of EV-derived FGL1 to PD-L1.