PMC8217641_01
Pathology results. H&E staining of the biopsy specimen showed poorly-differentiated NSCLC. IHC staining showed positive expression of Ki-67 and TopoII (x100).
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TTF-1, and Ki-67, but a negative expression of ALK and K-RAS ( Figure 1 ). The epidermal growth factor receptor (EGFR) mutation was not detected by using fluorescent polymerase chain reaction (PCR).
Radiological evaluation before and after therapy. The CT scan images demonstrated a significant reduction in pulmonary lesions.
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Luckily, a reassessment demonstrated that crizotinib had a significant effect on the patient ( Figure 2 ). The patient maintained stable disease on the alectinib treatment, with a PFS time of over ten months at last follow-up ( Figure 2 ).
Identification of the MRPS9-ALK fusion. (A) Sequencing reads of ALK and LINCO1159 & MRPS9 were visualized using the Integrative Genomics Viewer (IGV). (B) The structure schematic map of the MRPS9-ALK fusion locus. Intergenic region (IGR) of LINCO1159 & MRPS9 were fused to exon 18 of the ALK (yellow).
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Inc, Nanjing, China). A rare novel ALK fusion (IGR (upstream MRPS9)~ALK) ( Figure 3A ) was found using the NGS assay, in which the intact kinase domain of ALK was retained. The diagram of the MRPS9-ALK fusion is displayed in  Figure 3B . In addition, a frameshift mutation in exon 2 of RET (c.198delC; p.F66fs) was detected.