Performance of a RT-PCR Assay in Comparison to FISH and Immunohistochemistry for the Detection of ALK in Non-Small Cell Lung Cancer.

Patients with lung cancers harboring an activating anaplastic lymphoma kinase (ALK) rearrangement respond favorably to ALK inhibitor therapy. Fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) are validated and widely used screening tests for ALK rearrangements but both methods have limitations. The ALK RGQ RT-PCR Kit (RT-PCR) is a single tube quantitative real-time PCR assay for high throughput and automated interpretation of ALK expression. In this study, we performed a direct comparison of formalin-fixed paraffin-embedded (FFPE) lung cancer specimens using all three ALK detection methods. The RT-PCR test (diagnostic cut-off ΔCt of ≤8) was shown to be highly sensitive (100%) when compared to FISH and IHC. Sequencing of RNA detected full-length ALK transcripts or EML4-ALK and KIF5B-ALK fusion variants in discordant cases in which ALK expression was detected by the ALK RT-PCR test but negative by FISH and IHC. The overall specificity of the RT-PCR test for the detection of ALK in cases without full-length ALK expression was 94% in comparison to FISH and sequencing. These data support the ALK RT-PCR test as a highly efficient and reliable diagnostic screening approach to identify patients with non-small cell lung cancer whose tumors are driven by oncogenic ALK.

Detection of a TRAF1-ALK fusion in an anaplastic large cell lymphoma patient with chemotherapy and ALK inhibitor-resistant disease.

BACKGROUND: The anaplastic lymphoma kinase (ALK) gene encodes a receptor tyrosine kinase, which was first identified as the fusion partner of the nucleophosmin (NPM1) gene in the recurrent t(2;5)(p23;q35) found in a subset of anaplastic large cell lymphoma (ALCL). Several distinct, non-NPM1, ALK fusions have subsequently been described in lymphomas and other tumor types. All of these fusions result in the constitutive expression and activation of ALK and ALK signaling pathways, ultimately leading to the malignant phenotype. CASE REPORT: A non-NPM1 fusion partner of ALK was identified in a 32-year-old Caucasian male ALCL patient whose disease was refractory to standard chemotherapy and autologous stem cell transplantation, and exhibited a poor response to a first-generation ALK inhibitor. Non-allele-specific ALK RT-qPCR revealed ALK overexpression and 5' RACE PCR revealed that the patient's lymphoma expressed a TRAF1-ALK fusion. CONCLUSIONS: We report the case of an ALCL patient whose tumor harbored the newly recognized TRAF1-ALK fusion and describe the clinical outcome after treatment with an ALK inhibitor. The short survival of our patient may reflect a propensity toward aggressive behavior in lymphomas that express this ALK fusion.