Abstract 2134: Standard immunohistochemistry efficiently screens for ALK rearrangements in differentiated thyroid cancer

The anaplastic lymphoma kinase (ALK) gene is frequently rearranged in various types of cancer, and is highly responsive to the target therapeutics. We developed a pipeline to detect ALK rearrangement in a large group of Korean thyroid cancer patients. We screened 474 malignant or benign thyroid tumor cases to find ALK fusion. The expression and translocation of the ALK gene were analysed by immunohistochemistry (IHC), fluorescence in situ hybridisation (FISH), and digital multiplexed gene expression (DMGE) using formalin-fixed paraffin embedded tissues. Four cases of ALK rearrangement were screened out of 474 patients by IHC, which were validated by performing FISH for 189 samples. On the other hand, DMGE analysis using Nanostring could detect three out of four IHC positive cases. Two ALK rearrangements were Striatin (STRN)-ALK fusion, identified by 5′ RACE analysis. ALK rearrangements were found exclusively in the BRAF wild type papillary carcinoma. Given the wide availability and accuracy for detecting ectopic ALK expression in the thyroid, we suggest that IHC based screening can be used as a practical method for identifying patients with ALK rearranged differentiated thyroid cancer. Citation Format: Gahee Park, Tae Hyuk Kim, Hae-Ock Lee, Jung Ah Lim, Jae-Kyung Won, Hye Sook Min, Kyu Eun Lee, Do Joon Park, Young Joo Park, Woong-Yang Park. Standard immunohistochemistry efficiently screens for ALK rearrangements in differentiated thyroid cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2134. doi:10.1158/1538-7445.AM2015-2134