Somatic mutations of the MET oncogene are selected during metastatic spread of human HNSC carcinomas

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• Metastatic cancer arises from accumulated mutations affecting growth, survival, and spread.
• Genes controlling cancer cell spreading, crucial for metastasis, remain largely unidentified.
• Head and neck squamous cell carcinomas (HNSCC) are aggressive cancers where understanding metastatic drivers is critical.

Purpose of the Study:

• To identify genes and mutations responsible for the metastatic spread of HNSCC.
• To investigate the role of the MET oncogene in HNSCC metastasis.
• To determine if specific MET mutations contribute to cancer progression and invasiveness.

Main Methods:

• Analysis of lymph node metastases from HNSCC patients.
• Identification and characterization of somatic mutations in the MET oncogene.
• Functional studies involving transfection of cells with mutated MET receptors.
• Quantification of mutant MET allele representation in primary tumors versus metastases.

Main Results:

• Two somatic mutations in the MET oncogene, Y1230C and a novel Y1235D, were identified in HNSCC metastases.
• The Y1230C mutation is a known germline mutation predisposing to hereditary renal cell carcinoma.
• Mutated MET receptors exhibited constitutive activity, conferring an invasive phenotype to transfected cells.
• Mutant MET alleles were highly represented in metastases, indicating selection and clonal expansion during metastatic spread.

Conclusions:

• The MET oncogene plays a significant role in driving HNSCC metastasis.
• Specific MET mutations can lead to constitutive receptor activity and promote cancer cell invasiveness.
• Cells expressing mutant MET undergo clonal expansion, highlighting MET as a key oncogene in HNSCC progression to metastasis.