PMC8445031_01
Baseline data: (A) Positron emission tomography-computed tomography (PET-CT) image. (B) Representative histopathological image of the tumor (H&E staining). (C) Next-generation sequencing showed an L861Q mutation in the epidermal factor receptor exon 21.
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Positron emission tomography-computed tomography (PET-CT) revealed a fluoro-2-deoxy-d-glucose (FDG)-positive lesion in the left middle lung lobe and metastases in multiple bones (Figure 1A). TTF-1 staining (Figure 1B). To identify potentially actionable mutations of the patient, paired NGS-based genetic testing of 1,021 cancer-related genes was performed with both circulating free DNA from plasma and DNA extracted from the leukocytes (Geneplus-Beijing Ltd., Beijing, China). EGFR L861Q mutations (allelic fraction, AF=6.1%) in exon 21 were identified by next-generation sequencing (NGS) of the plasma, with concurrent TP53 N239S mutation in exon 7 and RB1 mutations (Figure 1C).
Representative computed tomography images at various points (A) and mutation analysis of the patient's plasma (B) before and after osimertinib treatment.
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He experienced progressive disease of the right frontal lung lobe, subcarinal lymph node, and brain metastases after a progression-free survival (PFS) of 15.0 months (Figure 2A). The AF of the L861Q mutation increased to 73.2%, with TP53 and RB1 mutations and absence of EGFR T790M (Figure 2B).
Schematic of the course of disease management, showing different treatment regimens prescribed and the results of the mutation analyses.
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The last follow-up was in November 2020, after which the patient passed away, with an overall survival of 19 months (Figure 3).