Identifying, Diagnosing, and Grading Malignant Peripheral Nerve Sheath Tumors in Genetically Engineered Mouse Models

Area of Science:

• Oncology
• Genetics
• Pathology

Background:

• Neurofibromatosis type 1 (NF1) patients develop plexiform neurofibromas (PNs) that can progress to malignant peripheral nerve sheath tumors (MPNSTs).
• Existing genetically engineered mouse (GEM) models with Nf1 ablation do not fully recapitulate PN-MPNST progression.
• A novel GEM model, P0-GGFβ3 mice, overexpressing neuregulin-1 (NRG1) in Schwann cells, develops PNs that frequently progress to MPNSTs.

Purpose of the Study:

• To validate the P0-GGFβ3 GEM model for studying NF1-associated tumorigenesis.
• To establish and describe methodologies for diagnosing and grading peripheral nervous system neoplasms in GEM models.
• To compare the pathology of GEM-derived tumors with human NF1-associated PNs and MPNSTs.

Main Methods:

• Histologic, immunohistochemical, and histochemical analyses for diagnosing and grading PNs and MPNSTs in GEM models.
• Distinguishing GEM-derived neoplasms from other mimicking tumor types.
• Establishing and characterizing early-passage GEM MPNST cell cultures using immunocytochemistry.
• Verifying tumorigenicity of GEM MPNST cultures through allograft establishment.

Main Results:

• The P0-GGFβ3 GEM model, including P0-GGFβ3;Trp53^+/- mice, develops PNs and MPNSTs.
• Specialized diagnostic and grading methodologies were applied to these GEM models.
• GEM-derived MPNSTs were successfully cultured and their tumorigenicity confirmed via allografts.
• Pathology of murine tumors was critically compared to human counterparts.

Conclusions:

• The described methodologies enable accurate diagnosis and grading of peripheral nervous system neoplasms in GEM models.
• The P0-GGFβ3 GEM model accurately recapitulates the pathology of human NF1-associated PNs and MPNSTs.
• These GEM models are valuable tools for investigating NF1 tumorigenesis and preclinical therapeutic development.