Genomic landscape and clinical correlates of ALK fusions in colorectal cancer.

205 Background: Anaplastic lymphoma kinase (ALK) fusions are well‐established therapy targets in non‐small cell lung cancer but can also occur in other tumor types. In colorectal cancer (CRC), ALK fusions were first described in 2012, and have since been detected by both tissue and liquid biopsies and linked to response to ALK inhibitors. This study characterizes the genomic and clinical features of ALK fusions in CRC. Methods: 56,206 advanced (stage III & IV) CRC tumors underwent hybrid capture based comprehensive genomic profiling (CGP) to identify all classes of genomic alterations (GA). Microsatellite instability/mismatch repair (MSI/MMR) status, tumor mutational burden (TMB), genomic ancestry, and homologous recombination deficiency (HRD) status were determined by sequencing. PD-L1 expression was determined by IHC using the Dako TPS score (0% = negative; 1-49% = low positive and >50% = high positive). Results: 63 (0.1%) CRC tumors featured ALK fusions (ALKfus+). In contrast to CRC tumors negative for ALK fusions (ALKfus-), ALKfus+ CRC were older (median age 68 years vs 62 years; p=.012) and less frequently male gender (34.9% vs 56.0%; p