Confirmation of non-small cell lung cancer (NSCLC) diagnosis using ALK testing and genetic profiling in patients presenting with carcinoma of unknown primary site (CUP).

Abstract

e19062 Background: Emerging data suggest real-time reverse transcriptase-polymerase chain reaction (RT-PCR) tumor profiling can predict the primary site in CUP. We report on CUP patients (pts) predicted to have NSCLC by RT-PCR, in whom detection of ALK rearrangements provided further diagnostic support. Methods: 4 pts were diagnosed with CUP based on standard clinical, radiographic, pathologic evaluation with immunohistochemistry (IHC), and bronchoscopy/endoscopy where indicated. All pts had a RT-PCR assay (CancerTYPE ID, bioTheranostics, Inc.) performed on tumor specimens for the purpose of predicting a primary site. Tissue was also tested for ALK by FISH using a break-apart probe. Results: Pt characteristics are shown (Table). RT-PCR results prompted ALK testing in Pts 2 and 3. ALK testing and RT-PCR testing were performed concurrently in Pts 1 and 4. Each specimen was diagnosed as lung adenocarcinoma (AC) by RT-PCR gene profiling, and also tested positive for an EML4-ALKrearrangement. All pts are being followed for clinical outcome. Conclusions: Gene expression profiling in CUP diagnosed lung AC in 4 pts who also had ALK rearrangements supporting the diagnosis. Identifying ALK-positive NSCLC among pts who present with CUP improves the site-specific treatment options. [Table: see text]