A pilot exome sequencing study suggests that germline variants influence methotrexate-induced toxicities in pediatric...

Area of Science:

• Genomics
• Pediatric Oncology
• Pharmacogenetics

Background:

• Osteosarcoma (OS) treatment response varies significantly among pediatric patients.
• Inherited genetic variations are increasingly recognized as contributors to this variable response.
• Previous studies on genetic factors in pediatric OS have yielded inconsistent results and often examined limited gene sets.

Purpose of the Study:

• To identify germline coding variations associated with individual differences in adverse events.
• To investigate patient response to methotrexate, cisplatin, and doxorubicin chemotherapy.
• To explore genetic underpinnings of treatment variability in localized osteosarcoma.

Main Methods:

• Conducted an exome-wide association study in 24 pediatric osteosarcoma patients.
• Utilized the SNP-Set (Sequence) Kernel Association Test (SKAT) optimized for small sample sizes.
• Analyzed associations with adverse events like neutropenia and hepatotoxicity.

Main Results:

• Identified significant gene sets associated with methotrexate-induced neutropenia and hepatotoxicity (FDR < 0.05).
• Some identified genes are located in regions previously linked to similar phenotypes (e.g., leukocyte count, alkaline phosphatase levels).
• This pilot study highlights potential pharmacogenes beyond traditional drug metabolism and transport categories.

Conclusions:

• Further validation in larger cohorts and functional studies are necessary.
• This research supports the investigation of whole-genome variants for novel pharmacogene discovery in osteosarcoma.
• Findings suggest a broader genetic basis for chemotherapy response variability in pediatric cancer.