Abstract 4323: ALK overexpression is associated with activation of PI3K/AKT signaling pathway in PTC

Aberrant activation of anaplastic lymphoma kinase (ALK) gene caused by mutation, rearrangement or overexpression plays a fundamental role in tumorigenesis in several tumors and represents an important therapeutic target. Currently, only limited data is available on thyroid cancer with respect to the genetic alteration of ALK. Therefore we investigate the ALK overexpression and amplification, and its correlation with various clinicopathological features and molecular biomarkers in a large cohort of 1040 Middle Eastern PTC. In our study, ALK protein expression was determined by immunohistochemistry. ALK gene amplification and rearrangement were analyzed by in situ hybridization (FISH). We also correlated the data with clinicopathological characteristics and other molecular markers. Our data showed that ALK is overexpressed in 136 of the 997 (13.6%) PTC samples. ALK amplification and rearrangement were not observed by FISH. ALK overexpression was significantly associated with surgical margin, but had no effect on the survival of PTC patients. Interestingly, ALK overexpression was found to be significantly correlated with the higher expression of pAKT and PIK3CA in PTC samples, suggesting that ALK overexpression is associated with activation of PI3K/AKT signaling pathway in PTC. In addition, ALK overexpression is also correlated with overexpression of anti-apopototic marker XIAP and BCL-XL and cell cycle regulatory marker SKP2. Altogether, our results suggest that ALK overexpression presents in a small subset of samples and is not associated with survival in PTC. However ALK overexpression is significantly correlated with PI3K/AKT signaling pathway and might provide a potential therapeutic target for PTC patients with ALK overexpression. Citation Format: Rong Bu, Sarita Prabhakaran, Shaham Beg, Zeenath Jehan, Abdul K. Siraj, Maqbool Ahmed, Azhar Hussain, Saif A. Alsobhi, Fouad Al-Dayel, Shahab Uddin, Khawla S. Al-Kuraya. ALK overexpression is associated with activation of PI3K/AKT signaling pathway in PTC. [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 4323. doi:10.1158/1538-7445.AM2015-4323