KRAS and non-small cell lung carcinoma: In cohorts from the USA for non-small cell lung cancer (NSCLC) patients, high PD-L1 expression (≥ 50%) was observed in 34% to 55% of tumors with alterations such as ALK and BRAF V600E, whereas lower rates were found in classic EGFR and KRAS mutant tumors [204].