Genomic profiling of myeloid sarcoma by array comparative genomic hybridization

Area of Science:

• Oncology
• Genetics
• Pathology

Background:

• Myeloid sarcoma (MS) is characterized by immature myeloid cell tumors at extramedullary sites.
• Accurate genomic profiling is crucial for understanding MS pathogenesis and guiding treatment.
• Conventional cytogenetics can sometimes be limited in detecting subtle genomic alterations.

Purpose of the Study:

• To evaluate the utility of array comparative genomic hybridization (array-CGH) in detecting genomic abnormalities in myeloid sarcoma (MS) tissue.
• To compare array-CGH findings with conventional cytogenetics (CC) and fluorescence in situ hybridization (FISH).
• To assess the potential of array-CGH in cases with non-diagnostic bone marrow samples.

Main Methods:

• Seven myeloid sarcoma (MS) cases with various extramedullary sites were analyzed.
• Array comparative genomic hybridization (array-CGH) was performed using a BAC clone-based genome-wide array.
• Data analysis involved DNAcopy software and custom heuristics; results were compared with CC/FISH where applicable.

Main Results:

• All seven MS cases exhibited genomic abnormalities detected by array-CGH.
• Unbalanced genomic abnormalities were confirmed in five cases by CC/FISH, including specific chromosomal losses and gains.
• Array-CGH identified deletions, translocations, and breakpoints missed or questionable by CC.
• Chromosome 8 abnormalities were most frequent (3/7 cases).
• Identical genomic abnormalities were found in MS and synchronous bone marrow samples in two cases.

Conclusions:

• Array-CGH is a powerful tool for screening myeloid sarcoma tissue for unbalanced genomic abnormalities.
• This technique can identify chromosomal aberrations when concurrent bone marrow samples are non-analyzable or non-leukemic.
• Array-CGH enhances the detection of genomic alterations in myeloid sarcoma, complementing conventional methods.