Concomitant Rare KRAS and BRAF Mutations in Lung Adenocarcinoma: A Case Report

In July 2020, an active smoker, 63-year old man was admitted to the oncology unit of A.O.R.N. Sant’Anna e San Sebastiano (Caserta, Italy). Chest radiology highlighted right pleural effusion. Total-body CT scanning revealed a solid lesion with lobulated contours in the apical segment of the upper right lobe. The patient’s oncologist requested a molecular assessment of EGFR, ALK, ROS1, BRAF, and KRAS, as well as an evaluation of PD-L1 expression level. To this end, we carried out NGS analysis, on DNA extracted from cytospins, by adopting a custom-designed NGS panel (SiRe®). Overall, no actionable mutations in the tested genes were identified. Conversely, concomitant BRAF exon 11 p.G469A and a KRAS exon 4 p.A146T mutations were detected. Owing to the limited data on the presence of KRAS exon 4 p.A146T point mutation in lung adenocarcinoma patients, a further molecular confirmatory analysis was carried out with a dedicated KRAS cartridge on a fully automated real time polymerase chain reaction. When DNA was extracted from the TTF-1 positive tumor cell slide, the same KRAS alteration was observed. Unfortunately, the patient died in August 2020 before having the chance to start any type of treatment.