Telomere alterations in neurofibromatosis type 1-associated solid tumors

Area of Science:

• Oncology
• Genetics
• Molecular Biology

Background:

• Neurofibromatosis type 1 (NF1) is a genetic disorder predisposing individuals to various tumors.
• The role of telomere maintenance mechanisms, including Alternative Lengthening of Telomeres (ALT), in NF1-associated solid tumors remains understudied.
• Telomere length abnormalities and ALT are critical in cancer progression and can influence patient outcomes.

Purpose of the Study:

• To investigate the prevalence and significance of ALT and telomere length abnormalities in NF1-associated solid tumors.
• To analyze the association between these telomere alterations and patient survival.
• To compare findings in NF1-gliomas and NF1-associated malignant peripheral nerve sheath tumors (MPNSTs).

Main Methods:

• Utilized a telomere-specific fluorescence in situ hybridization (FISH) assay to classify tumors.
• Evaluated 426 tumors from 256 NF1 patients and 99 MPNST samples (sporadic or unknown NF1 status).
• Assessed telomere lengths (long, short, normal) and ALT status in glioma and MPNST cohorts.

Main Results:

• ALT was found in 60% of high-grade NF1-gliomas versus 19% of low-grade gliomas.
• In NF1-MPNSTs, ALT was present in 12% of cases.
• ALT-positive gliomas showed significantly decreased overall survival (p < 0.0001).
• Short telomeres in NF1-MPNSTs were associated with superior overall survival (p = 0.003).
• Telomere length alterations were more prevalent than ALT across NF1 tumors.

Conclusions:

• Alternative Lengthening of Telomeres (ALT) is present in a subset of NF1-associated solid tumors, predominantly in malignant subtypes.
• Telomere length abnormalities are more common than ALT in NF1-associated cancers.
• These findings highlight the importance of telomere biology in NF1 tumorigenesis and suggest potential prognostic implications.