Biological implications of deletion p53 by fluorescence in situ hybridization in multiple myeloma

Abstract

Background: Multiple myeloma (MM) is a clonal plasma cell disorder characterized by heterogeneous complex genetic abnormalities. Due to the low proliferative index of plasma cells, conventional cytogenetic (CC) analysis is hampered in MM. Interphase fluorescence in situ hybridization (FISH) along with CC enhances the sensitivity of detection. The study aims to investigate the diagnostic yield and prevalence of P53 deletion in patients with MM. Materials and Methods: Cytogenetic analysis and FISH were performed on 41 MM patients. Results: Our study showed that 55–65 years of age range among all individuals, predominantly affected by the disease. The cytogenetic analysis detected abnormal karyotype in 12% (5/41), normal karyotype in 66% (27/41), and culture failure in 22% (9/41). Abnormal karyotype showed numerical abnormalities such as hyperdiploidy 5% (n = 2) and hypodiploidy 7% (n = 3%). Chromosomes 5, 9, 11, and 21 were common gains among hyperdiploid cases. Chromosome 7, 17, 22 and Y were the common missing chromosome in hypodiploid cases. P53 gene deletion is a rare genetic event and difficult to identify using CC. FISH analysis of deletion 17p was detected in 15% (6/41). Out of six cases, two cases showed deletion of 17p region, three cases showed monosomy 17, and one case showed amplification signals for chromosome 17. Conclusion: CC along with FISH increases the rate of detection of abnormality in MM cases. P53 being less frequent is uncommon at initial diagnosis; increasing its incidence with advanced stage is considered one of the important prognostic factors in MM.

Keywords

• conventional cytogenetics
• fluorescence in situ hybridization
• multiple myeloma