PMC8415000_01
The lung target lesion on CT (white arrow). (A) Computed tomography (CT) scan showed a 2.7 cmx2.5 cm mass in the hilum of the right lung before treatment. (B) the imaging of lung target lesion after 1 month of alectinib treatment (1.4 cm x 1.1 cm lesions). (C) the imaging of lung target lesion after 4 months of alectinib treatment (1.2 cm x 1.0 cm lesions); (D) the imaging of lung target lesion after 7 months of alectinib treatment (1.1 cm x 0.7 cm lesions).
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On June 15, 2020, a contrast-enhanced computed tomography (CT) scan showed a 2.7 cmx2.5 cm mass in the hilum of the middle lobe of the right lung (Figure 1A) with mediastinal lymph node metastases and multiple metastases in the ribs and thoracic vertebras. A follow-up CT scan found that the lesions shrank to 1.4 cm x 1.1 cm after 1 month, 1.2 cm x 1.0 cm after 4 months, and 1.1 cm x 0.7 cm after 7 months of alectinib treatment (Figures 1B-D).
The rare PDK1-ALK and STRN-ALK fusion was identified in the same tumor tissue by next-generation sequencing (NGS). (A) sequencing reads of PDK1 and ALK by the Integrative Genomics Viewer. (B) sequencing reads of STRN and ALK by the Integrative Genomics Viewer.
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ALK-Ventana (D5F3), keratin 7, napsin A and thyroid transcription factor-1 were positive by immunohistochemistry staining, and then PDK1-ALK (P7:A20, allelic frequency: 12.85%), STRN-ALK (S3:A20, allelic frequency: 27.11%) double-fusion (Figures 2A, B) and a variable splicing mutation in exon 9 of TP53 (allelic frequency: 4.84%) were identified in the same tumor tissue by DNA-based NGS (mean depth of the reads was 1200X), while the other driver gene mutations, including EGFR, KRAS and ROS1, were not detected.