Cytogenetic testing by fluorescence in situ hybridization is improved by plasma cell sorting in multiple myeloma

t(11;14) status is stable between diagnosis and relapse and concordant between detection methodologies based on fluorescence in situ hybridization and next-generation sequencing in patients with multiple myeloma

Multiple myeloma (MM) is associated with a wide variety of recurrent genomic alterations. The most common translocation in MM is t(11;14). In this retrospective, single-center, non-interventional study, patients' bone marrow samples were examined at diagnosis and at relapse(s) following treatment with anti-myeloma regimens to determine whether t(11;14) status was stable over time. This stability cohort consisted of 272 patients, of whom 118 were t(11;14)-positive at diagnosis and 154 were negative. All patients in the stability cohort retained the same t(11;14) status at relapse that they had at diagnosis of MM. Sixteen patients who had t(11;14)-positive MM at diagnosis had multiple longitudinal assessments by fluorescence in situ hybridization (FISH) at relapse events and remained t(11;14)-positive across all timepoints. Patients who had t(11;14)-positive disease at diagnosis of monoclonal gammopathy of unknown significance or smoldering MM also retained t(11;14) positivity through MM diagnosis and relapse. The t(11;14) fusion patterns also remained constant for 90% of patients. For detection of t(11;14), results from FISH and next-generation sequencing (NGS) were compared to determine the rate of concordance between these two methods. This concordance cohort contained 130 patients, of whom 66 had t(11;14)-positive disease and 64 were t(11;14)-negative. In this sample set, the concordance between FISH- and NGS-based detection of t(11;14) was 100%. These results strongly suggest that the t(11;14) rearrangement remains stable during the full disease course in patients with MM and can be detected by FISH- and NGS-based methodologies.

Chromosomal defects in multiple myeloma

Multiple myeloma is a plasma cell neoplasm driven by primary (e.g. hyperdiploidy; IGH translocations) and secondary (e.g. 1q21 gains/amplifications; del(17p); MYC translocations) chromosomal events. These are important to detect as they influence prognosis, therapeutic response and disease survival. Currently, cytogenetic testing is most commonly performed by interphase fluorescence in situ hybridisation (FISH) on aspirated bone marrow samples. A number of variations to FISH methodology are available, including prior plasma cell enrichment and incorporation of immunophenotypic plasma cell identification. Other molecular methods are increasingly being utilised to provide a genome-wide view at high resolution (e.g. single nucleotide polymorphism (SNP) microarray analysis) and these can detect abnormalities in most cases. Despite their wide application at diagnostic assessment, both FISH and SNP-array have relatively low sensitivity, limiting their use for identification of prognostically significant low-level sub-clones or for disease monitoring. Next-generation sequencing is increasingly being used to detect mutations and new FISH techniques such as by flow cytometry are in development and may address some of the current test limitations. Here we review the primary and secondary cytogenetic aberrations in myeloma and discuss the range of techniques available for their assessment.

Application of Fluorescence In Situ Hybridization (FISH) in Oral Microbial Detection

Varieties of microorganisms reside in the oral cavity contributing to the occurrence and development of microbes associated with oral diseases; however, the distribution and in situ abundance in the biofilm are still unclear. In order to promote the understanding of the ecosystem of oral microbiota and the diagnosis of oral diseases, it is necessary to monitor and compare the oral microorganisms from different niches of the oral cavity in situ. The fluorescence in situ hybridization (FISH) has proven to be a powerful tool for representing the status of oral microorganisms in the oral cavity. FISH is one of the most routinely used cytochemical techniques for genetic detection, identification, and localization by a fluorescently labeled nucleic acid probe, which can hybridize with targeted nucleic acid sequences. It has the advantages of rapidity, safety, high sensitivity, and specificity. FISH allows the identification and quantification of different oral microorganisms simultaneously. It can also visualize microorganisms by combining with other molecular biology technologies to represent the distribution of each microbial community in the oral biofilm. In this review, we summarized and discussed the development of FISH technology and the application of FISH in oral disease diagnosis and oral ecosystem research, highlighted its advantages in oral microbiology, listed the existing problems, and provided suggestions for future development..