An Unusual Increase in the CD38 Marker Observed in a Multiple Myeloma Patient With t(11;14) Translocation: A Case Report.

Multiple myeloma (MM) is one of the world's most recognized bone marrow (BM) cancers. It is considered a plasma cell dyscrasia in which normal plasma cells transform into malignant cells that produce large quantities of an abnormal immunoglobulin called monoclonal protein better known as M protein. This, in turn, is responsible for many of its bone and kidney-related manifestations. Many translocations are associated with the disease, such as t(11;14), t(4;14), and t(14;16). Of these, the most common is t(11;14). In this subset of MM, there is a specific genetic alteration affecting the CCND1 gene. Typically inactive in plasma cells, this gene, when disrupted, promotes uncontrolled cell proliferation. Simultaneously, there is a reduction in CD38 levels, a protein typically elevated in MM patients. This combination of genetic and protein expression is a defining feature of this subgroup within the MM spectrum. In this report, we present a case of a 75-year-old male who was referred by an oncologist for comprehensive diagnostic testing. He was found to have significant hyperploidy involving trisomy 9 and an extra copy of CCND1 with concomitant trisomy 11q confirming a t(11;14) translocation. Further workup involving cytology revealed that the patient also expressed elevated levels of CD38, which, given this mutation, would be expected to be low in this patient population. We aim to highlight the importance and prognostic value of this mutation and further add to the already growing body of literature associated with this disease.