(PA-241) Clinical Impact of Cytogenetic Abnormalities and Detection Discordance between Conventional Karyotyping and FISH in Multiple Myeloma

Introduction:  HCytogenetic abnormalities at diagnosis are key prognostic factors in multiple myeloma (MM). This study aimed to evaluate the frequency of chromosomal aberrations in MM patients and their association with overall survival (OS), and to analyze discrepancies between conventional cytogenetic analysis (CCA) and fluorescence in situ hybridization (FISH).

Methods:   In this retrospective cohort study, 98 newly diagnosed MM patients at Dong-A University Hospital were included. All had results available from both CCA (G-banding) and FISH analysis, which targeted the following abnormalities: del(1p32), dup(1q21), t(4;14), t(6;14), t(11;14), CEP12, del(13q), IGH rearrangement, t(14;16), t(14;20), and TP53 deletion. Clinical variables including hemoglobin, platelet count, calcium, albumin, creatinine, β2-microglobulin, ISS stage, M-protein subtype, chemotherapy regimen, and stem cell transplantation status were reviewed. The normal karyotype group served as the comparator.

Results:   

The median age was 66 years, and the median follow-up duration was 24.7 months. Cytogenetic abnormalities were identified in 82.6% of patients. Anemia was significantly more common in the abnormal karyotype group (P=0.01). Among clinical variables, only age >65 years was significantly associated with inferior OS (P=0.02). The most common abnormalities were del(13q) (17.9%), dup(1q21) (13.8%), hyperdiploidy (11.9%), and t(11;14) (9.2%). Among these, del(13q) (P=0.03), hypodiploidy (P=0.008), and dup(1q21) (P=0.01) were significantly associated with worse OS. Notably, 33.7% of cases showed discordant results between CCA and FISH. In particular, patients with dup(1q21) detected by CCA had significantly poorer survival outcomes (P=0.002).

Conclusions:   This study confirms that specific cytogenetic abnormalities, especially del(13q), hypodiploidy, and dup(1q21), are associated with inferior survival in MM. Moreover, discrepancies between CCA and FISH were common, and in the case of dup(1q21), detection by CCA provided more prognostic relevance. These findings highlight the complementary roles of both cytogenetic techniques and suggest the need for integrated interpretation in MM prognostication.