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Updated: Apr 18, 2026
Comparative Lesions Analysis Through a Targeted Sequencing Approach
Published on: November 5, 2019
Genomic copy number alterations of primary and secondary metastasizing pleomorphic adenomas
Fernanda Viviane Mariano1, Rogério de Oliveira Gondak2, Antonio Santos Martins3
1Pathology Department, Faculty of Medicine, State University of Campinas (UNICAMP), Campinas, Brazil.
Aims:
Metastasizing pleomorphic adenoma (MPA) is a rare tumour, and its mechanism of metastasis still is unknown. To date, there has been no study on MPA genomics. We analysed primary and secondary MPAs with array comparative genomic hybridization to identify somatic copy number alterations and affected genes.
Methods And Results:
Tumour DNA samples from primary (parotid salivary gland) and secondary (scalp skin) MPAs were subjected to array comparative genomic hybridization investigation, and the data were analysed with NEXUS COPY NUMBER DISCOVERY. The primary MPA showed copy number losses affecting 3p22.2p14.3 and 19p13.3p123, and a complex pattern of four different deletions at chromosome 6. The 3p deletion encompassed several genes: CTNNB1, SETD2, BAP1, and PBRM1, among others. The secondary MPA showed a genomic profile similar to that of the primary MPA, with acquisition of additional copy number changes affecting 9p24.3p13.1 (loss), 19q11q13.43 (gain), and 22q11.1q13.33 (gain).
Conclusion:
Our findings indicated a clonal origin of the secondary MPA, as both tumours shared a common profile of genomic copy number alterations. Furthermore, we were able to detect in the primary tumour a specific pattern of copy number alterations that could explain the metastasizing characteristic, whereas the secondary MPA showed a more unbalanced genome.
Insights
Genomic analysis of metastasizing pleomorphic adenoma (MPA) reveals shared copy number alterations between primary and secondary tumors, suggesting clonal origin. Specific alterations in the primary MPA may drive its metastatic potential.
Area of Science:
- Oncology
- Genetics
- Pathology
Background:
- Metastasizing pleomorphic adenoma (MPA) is a rare neoplasm with an unknown metastatic mechanism.
- No previous genomic studies have been conducted on MPA.
Observation:
- Array comparative genomic hybridization (aCGH) was used to analyze primary (parotid) and secondary (scalp) MPA tumors.
- Genomic profiles were compared to identify somatic copy number alterations (SCNAs).
Findings:
- The primary MPA exhibited copy number losses on chromosomes 3p and 19p, and complex deletions on chromosome 6.
- Key genes like CTNNB1, SETD2, BAP1, and PBRM1 were affected by the 3p deletion.
- The secondary MPA shared SCNAs with the primary tumor and acquired additional gains and losses on chromosomes 9, 19, and 22.
Implications:
- The shared genomic alterations support a clonal origin for the secondary MPA.
- Specific SCNAs in the primary MPA may be responsible for its metastatic capability.
- The secondary MPA presented a more genomically unbalanced state.
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