Despite recent strides in mapping the mutational landscape of chronic lymphocytic leukemia (CLL) there is still limited information regarding the clinical impact of some less common gene mutations in the treatment of CLL. As next generation sequencing (NGS) has become more readily available physicians have more information about their patient’s genome, but this information is often lacking in context.
Using a commercially available NGS platform researchers from Weill Cornell Medicine identified a high prevalence of mutations in the FAT1 gene in people with CLL. FAT1 plays a role in regulating WNT signaling and tumor suppression and mutations have previously been associated with leukemia. Given the prevalence of FAT1 mutations in our CLL database and evidence suggesting FAT1 contributes to tumor growth, researchers investigated the clinical impact of FAT1 mutations.
Altogether 172 patients were included in the study. Nineteen (11%) patients were found to have a FAT1 mutation and 153 (89%) were lacking the mutation. In total 21 mutations were identified with 17 being unique. No significant differences were found between groups based on age or co-occurrence of high risk mutations, although 17p deletions occurred significantly more in mutated FAT1 patients (24%) compared to people lacking the mutation (7%). Mutated FAT1 patients had a significantly shorter TTFT at 50 months compared to 143 months for people lacking the mutation.
Researchers identified a higher prevalence of FAT1 mutations in untreated CLL patients than previously reported. FAT1 was found to associate with the 17p deletion, but no other high-risk mutations. We also found a vast difference in TTFT between mutated FAT1 and those lacking the mutation, although there was no difference in response rates when treated with novel agents.
These findings suggest that FAT1 mutations may be more common in patients, who have yet to receive treatment than commonly supposed. Results warrant additional research to investigate the influence of FAT1 mutations and association with the 17p deletion.