[TTF-1-negative lung adenocarcinoma: special features of systemic treatment].

The identification of biomarker-adjusted treatments has revolutionized the treatment landscape of metastatic lung cancer and improved survival for a relevant share of patients with actionable genomic alterations and those benefiting from checkpoint inhibitors (CPI). Given a clear correlation between the expression of "programmed death ligand 1" (PD-L1) and treatment efficacy of CPI, immunochemotherapy is used in patients with a PD-L1 expression <50%. The lower the PD-L1 expression, the more important is the chemotherapy backbone. For lung adenocarcinoma, there is currently a choice between pemetrexed- and taxane-based regimens. Retrospective data suggested superior survival using taxane-based treatment for patients negative for "thyroid transcription factor 1". A prospective randomized clinical trial is underway to verify this hypothesis.