Bacterial artificial chromosome array‐based comparative genomic hybridization using paired formalin‐fixed, paraffin‐embedded and fresh frozen tissue specimens in multiple myeloma

BACKGROUND: Multiple myeloma (MM) is a neoplasm of malignant plasma cells that often harbors many chromosomal aberrations. Currently, fresh frozen tissues (FT) are considered the most reliable for molecular genetic analysis; however, formalin‐fixed, paraffin‐embedded (FFPE) tissues are easily retrievable. Compared with conventional cytogenetics, bacterial artificial chromosome (BAC) array‐comparative genomic hybridization (CGH) allows more sensitive detection of chromosomal abnormalities. METHODS: The authors analyzed 7 paired FT and FFPE samples of bone marrow aspirate materials obtained from patients with MM in parallel to determine the efficacy of BAC array‐CGH using FFPE. RESULTS: Thirty‐four aberrations were identified, including 29 that were observed in both sample types, yielding 85% concordance. Nonrandom anomalies, including gains on 7q, 9q, 15q, and 19p and losses on 8p and 13q, were observed in paired samples from at least 2 patients. To verify these results, fluorescence in situ hybridization (FISH) was performed using probes specific for 7q and 15q, and gains were observed in the 4 samples that were examined. Furthermore, 1 of 3 samples from patients who had monoclonal gammopathy of undetermined significance that were tested also carried gain on 7q, suggesting that this aberration may be an early transforming event. CONCLUSIONS: The current results indicated that BAC array‐CGH can be effective using FFPE samples and is a sensitive method for the identification of nonrandom chromosomal aberrations in MM. Cancer 2009. © 2009 American Cancer Society.