Trends in 11;14 FISH Testing for Myeloma | Linda Baughn, PH.D. | IMS 2023

Hi, my name is Linda Bond and I'm one of the co-directors of the genomics laboratory at the Mayo Clinic. And it is here at within our laboratory where we perform the cytogenetic testing for the bone marrow biopsy for patients with multiple myeloma. When the biopsy comes to our laboratory, we perform an enrichment for the plasma cells and we then take those cells and put them onto glass slides and apply special probes. And these are essentially fish probes. And so fish is fluorescence in situ hybridization. And these are pieces of DNA that are matching the specific regions within the cell that we're interested in. We have different kinds of probes and they're also fluorescently labeled in different colors so that we can look under the microscope and see whether a patient has a split between different probes. Like for example, if a patient has an immunoglobulin heavy chain translocation, which can be seen in, for example, an 1114. So we look for a split of the IGH signal, but we also have probes that look for a fusion of the genes coming close together. So in cases like in 1114, you would have a fusion or closer proximity to 11 and chromosome 14. And we can see that by fish. So what we presented here at this meeting is we were curious in collaboration with Genentech to see how often patients are being tested for 1114. So this is a really interesting translocation because patients that have an 1114 are more likely to have higher levels of a gene called BCL2. And the drug Venetoclax is able to target BCL2. And because 1114 has higher BCL2 over a ratio over MCL1, for example, those cells are more sensitive to Venetoclax. Since 1114 is a useful biomarker to determine which patients would be sensitive to this drug, it is important to test for it at diagnosis. So in this study, we asked how many patients are being tested for 1114 over various periods of time. So in our whole study period of time, it was between 2011 and 2022. What we found over the course of this time is that fish testing for 1114 has increased. So in 2011, approximately half of the patients were being tested for 1114 by fish. And at the end of the study period in 2022, about 75% of patients were tested for fish. However, it does indicate that about 25% of patients are not actually tested at the time of diagnosis. The other aspect that we looked at is who is being tested for fish. So we looked at various demographics, for example, whether the patient is male or female, their different age groups, and also the self-identified race of that individual and socioeconomic status. We were pleased to see that there weren't actually major differences in who was being tested for fish based on these variables. So the bottom line is that fish testing is a really important activity to be performed at diagnosis. It can help manage the patient in terms of risk stratification and provide prognostic information. The good news is over time, fish testing has increased. We're not at 100% yet. That would be a great goal. But another good piece of news is that there does not appear to be obvious differences in who is being tested for fish independent of different variables. So thank you.