ALK Mutations Are Rare in Pheochromocytomas

Presentation Number: MON 401
Date of Presentation: April 3rd, 2017

Marcus Wallin*1, Samuel Backman2, Rajani Maharjan2, Per Hellman2 and Peyman Bjorklund2
1Uppsala University, Uppsala, Sweden, 2Uppsala University, Sweden

Abstract

Introduction
Pheochromocytomas and paragangliomas (PPGLs) are rare tumors originating from chromaffin cells of the adrenal medulla or sympathetic ganglia respectively. Approximately 70% of PPGLs harbor germline or somatic mutations in one of the 17 known genes.

ALK (Anaplastic Lymphoma Kinase) mutations are common in tumors originating from autonomic ganglia, however mutation status of ALK in PPGLs is unknown.

The aim of this study was to analyze the mutational status of ALK in a cohort of PPGLs.

Methods

DNA was extracted from 95 PPGLs and subjected to re-sequencing of all coding exons of ALK. DNA was also applied to high density SNP arrays and the results were subjected to subsequent CNV analysis.

Results

One of the 95 analyzed tumors harbored a p.R1275Q mutation. The mutation was absent in constitutional DNA and thus classified as somatic event. Copy number gain at the ALK locus was observed in four tumors while another four tumors exhibited copy number loss. One tumor showed copy number neutral loss of heterozygosity.

Conclusion

We conclude that somatic mutations in ALK are rare in PPGLs. Copy number variation results were inconclusive. ALK genetic or genomic aberrations may not play a pivotal role in PPGL tumorigenesis.

 

Nothing to Disclose: MW, SB, RM, PH, PB