Five cases of V600E-mutant lung adenocarcinoma with high expression of programmed death ligand 1.

We reported consecutive five patients with V600E-mutant recurrent or advanced non-small cell lung cancer who were identified between April 2016 and June 2019. All five patients had high programmed death ligand 1 (PD-L1) tumor proportion scores (50, 55, 75, 95 and 100%). Four of the five patients received regimens including pembrolizumab. Of them, one patient experienced a partial response, but two patients experienced progressive disease and one patient was not evaluable. Three of the four patients received regimens including pemetrexed were able to continue long-term treatment. The presence of a mutation may be associated with higher levels of PD-L1 expression. The effect of immune checkpoint inhibitors therapy in patients with mutation was similar to the previous reports in patients with previously treated advanced non-small cell lung cancer with PD-L1 tumor proportion score ≥50%. Chemotherapy regimens including pemetrexed may have a positive effect in patients with V600E-mutant lung adenocarcinoma. Accumulation of additional Case series is necessary to confirm our results.