Combining Gene Expression Profiling and Integrated Multidisciplinary Approaches to Improve Prognosis Prediction in Multiple Myeloma
Authors: Cerchione Claudio , Alassi Nour , Nappi Davide , Servili Chiara , Scarpi Emanuela , Cangini Delia , Ronconi Sonia , Ceccolini Michela , Paganelli Matteo , Coppola Luigi , Feliciani Giacomo , Rossi Alice , Mammoli Fabiana , Normanno Nicola , Musuraca Gerardo , Simonetti Giorgia , Martinelli Giovanni , Marchesini Matteo 
Published: December 2024

Introduction:
Despite the therapeutic advancements in the treatment of multiple myeloma (MM), particularly in the frontline setting where monoclonal antibodies anti-CD38 have become a backbone, a subset of patients continue to show early relapse and dismal prognosis. Biomarkers of high-risk (HR) and more efficient approaches of patient stratification are urgently needed to expedite an early identification of this subset of patients and to develop more tailored therapies. Soluble B-cell maturation antigen (sBCMA) is a reliable marker of disease with prognostic value. sBCMA levels increases with the disease status and patients with high levels showed the poorest outcome. Furthermore, gene expression profiling (GEP)-based stratification approaches have been recently valued as advanced systems for the early identification of HR MM patients.
We developed a monocentric prospective study to test SKY92 classification system among all consecutive patients referring to our Institute affected by smoldering (SMM), newly diagnosed (NDMM) and relapsed/refractory (RRMM) MM and evaluated its potential to predict or correlate with established HR markers of this disease.
Methods:
Patient's bone marrow aspirate, plasma and clinical data were collected in our Institute under approved protocol and according to the Declaration of Helsinki guidelines. Cytogenetics [t(4;14), del(17p) and gain(1q)] was carried out by FISH on purified CD138 positive plasma (PCs). SKY92 test was performed accordingly with manufacturing procedure using RNA extracted from enriched PCs samples (≥80%). Virtual FISH markers were obtained through microarray analyses and reported together with the SKY92 biomarker on a single report. sBCMA was detected using patient's peripheral plasma by an automated immunoassay (ELLA, Bio-Techne). The integration of SKY92 with ISS was performed by including class I ISS and low risk (LR) SKY92 patients in the standard risk (SR) group; classes II/III ISS and the LR SKY92 plus the class I ISS and HR SKY92 patients in the intermediate risk (IR) group; classes II/III ISS and the HR SKY92 patients in the HR group. The ANOVA test for multiple comparison (Tukey's correction), two-tailed unpaired t-test (Mann Whitney) and a chi-square (test for trend) were used when appropriate.
Results:
We enrolled a cohort of n=57 patients referring to our Institute (SMM n=12, NDMM n=30 and RRMM n=15). Proportion of patients with SKY92 HR increased from SMM (8.4%) to NDMM (36.7%) and RRMM (53.3%, p=0.0162). We tested the performance of virtual FISH in NDMM patients and we observed 100% accuracy (95% CI) (100.0-100.0) for both t(4;14) and gain(1q) and of 90.0 (71.4-100.0) for del(17p).
We measured the concentration of sBCMA in our patients' cohort and in healthy subjects (n=12, control) and, as expected, we observed a statistically significant increase of sBCMA in the blood of NDMM and RRMM with respect to SMM (p=0.0009, p=0.0222) and control (p&lt;0.0001, p=0.0010). Consistently with the literature, no statistically significant differences were observed among NDMM and RRMM. Thus, we hypothesize that SKY92 HR could capture patients with high levels of sBCMA. We compared the concentration of this disease biomarker among SR and HR including SMM, NDMM and RRMM patients and we observed increased levels of sBCMA in HR patients with respect to SR (p=0.0049). A risk-based intragroup comparison showed a similar trend in SMM and RRMM though not statistically significant due to the low number of samples in these categories. Importantly, this result was confirmed in NDMM patients (p=0.0445).
However, in this category of MM patients ISS could partially recapitulate differences in sBCMA among risk classes with the only statistically significant difference between Class I and III (p=0.0381). Therefore, we combined ISS with SKY92 and we observed that n=3 patients considered as LR by ISS (Class I), were relocated to the IR from this analysis with an overall improvement in the distribution of sBCMA levels according to risk categories (SR vs HR p=0.0011, IR vs HR p=0.0036).
Conclusions:
The results of this first pilot Italian study, that in the next future will be framed in a national network contest, strengthen the prognostic relevance of SKY92 based on its potential to (i) predict HR cytogenetic markers of disease; (ii) capture MM patients with high levels of sBCMA supporting the introduction of this GEP-based tool in the clinical diagnostic practice.