Page 121 - 2021_09-Haematologica-web

A 3-gene signature in DLBCL
Supplementary Figures S3A and B). In univariate analyses only the age adjusted International Prognostic Index (aaIPI) score (intermediate-high vs. high), the COO classi- fication, MYC/BCL-2-DE status, NFKBIA and STAT3 lev- els determined by T-GEP, were significantly associated with OS (Table 2). As observed in the original studies,34,35 first-line ASCT consolidation was not associated with patient’s outcome.
In line with the data presented above (Online Supplementary Figure S1 and S2), a recursive partitioning analysis integrating the COO with MYC/BCL-2 status identified three main patient subgroups: two high risk subsets with similar outcome (ABC [n=40) and MYC/BCL-2 DEXP_mRNA GCB/U [n=27]) and a low-risk subgroup including non-DEXP_mRNA GCB/U DLBCL, (n=119) (Figure 2A). Evaluating the relative expression of the additional genes included in the panel across the three groups identified by the recursive partitioning analysis (non-DEXP_mRNA GCB/U, DEXP_mRNA GCB/U and ABC DLBCL patients) (Figure 2B), we found that only MYC, BCL-2 and NFKBIA were significantly deregulated in both the high-risk ABC and MYC/BCL-2 DEXP_mRNA GCB/U subgroups, which were characterized by similarly increased MYC and BCL-2 and lower NFKBIA mRNA lev- els compared to the low risk non-DEXP_mRNA GCB/U subset. The NFKBIA gene, a frequent target of deletions and mutations in DLBCL,23 encodes for the IkB-α protein, which is a central node of the NF-kB pathway and inhibits nuclear translocation and activity of the NF-kB transcrip- tion factors.40 STAT3 levels were similar in the high risk ABC and low risk non-DE GCB/U cases being significant- ly downregulated only in the DEXP_mRNA GCB/U sub- set. PIK3CA and PTEN levels did not vary significantly across different groups (Figure 2B).
Development of a three-gene prognostic signature combining MYC, BCL-2 and NFKBIA
In an effort to build a GEP signature aimed at refining current prognostication algorithms and suitable for clinical
Table 1. Patients characteristics.
Trial name RHDS0305
practice, we considered only those genes whose expres- sion was significantly associated with OS and differential- ly represented in both high risk (ABC and DEXP_mRNA GCB/U) versus low risk (non-DEXP mRNA GCB/U) patient subsets. Using these criteria, we constructed a prognostic signature considering three genes (MYC, BCL- 2 and NFKBIA), which combines the MYC/BCL-2 DEXP_mRNA status with NFKBIA expression (hereafter called MBN signature, see methods). Besides MYC and BCL-2, (defining the DEXP_mRNA status), NFKBIA emerged as the best survival predictor by gene ranking according to the predictive power (univariate z score) (Online Supplementary Figure S4). With this strategy, patients were divided in two risk categories characterized by different outcome: low risk patients (MBN-Sig low) had a very favorable prognosis (91% 5-year OS; 84% 5- year PFS), whereas high-risk patients (MBN-Sig high) had a significantly worse prognosis (64% 5-year OS; 59% 5- year PFS) (Figure 3A; Online Supplementary Figure S5A). Importantly the MBN signature retained its significance and outperformed the MYC/BCL-2 DEXP_mRNA status in multivariate analysis (Figure 3B; Online Supplementary Table S4). In fact, only the COO, the aaIPI score and the MBN signature were significantly associated with out- come in multivariate analyses (Figure 3B). These findings were confirmed in silico in a large independent validation cohort of 469 patients27 treated with R-CHOP (88% 5-year OS and 78% PFS for MBN-Sig low vs. 72% OS and 57% PFS for MBN-Sig high patients) (Figure 3C and D; Online Supplementary Figure S5B; Online Supplementary Table S5). The prognostic value of the MBN signature was further tested in a publicly available data set including 233 patients (from Lenz at al. 2008)36 treated with R-CHOP/R-CHOP-like regimens and in a real-life cohort (n=102 patients) with similar results (Online Supplementary Figure S6A and B). The MBN signature was able to identify a significant fraction of ABC-derived cases and about a third of GCB/U cases (Figure 3A and C; Online Supplementary Figure S6C and D).
DLCL04 P* RHDS0305 + DLCL04 N°ofpatients 87 99 - 186
Immuno-CHT alone Immuno-CHT + ASCT Median age, y (range) COO NanoString
ABC
GCB Unclassified
COO Hans IHC Non-GCB GCB-like
Stage (Ann Arbor) aaIPI score
Low-Low Intermediate (0-1) Intermediate-high (2)
High (3)
49 (56%)
38 (44%) 53 (21-65)
15 (17%) 53 (61%) 19 (22%)
58 (67%) 29 (33%) II-IV
-
55 (63%)
32 (37%)
56 (57%) - 43 (43%) - 52(18-65) -
25 (25%) ns 58 (59%) ns 16 (16%)
60 (61%)
39 (39%) ns
III-IV - ---
81 (82%) ns 136 (73%)
18 (18%) 0.005 50 (27%)
105 (56%) 81 (44%) 52 (18-65)
40 (21%) 111 (60%) 35 (19%)
118 (63%) 68 (37%) II-IV
*Two-sided Fisher’s exact test:N°:number;Immuno-CHT:immunochemotherapy;ASCT:autologous stem cell transplantation;y:years;COO:cell of origin;IHC:immunohistochem- istry; aaIPI: age adjusted international prognostic index; ns: not significant; GCB: germinal center B cells; ABC: activated B-cells; IHC: immunohistochemistry.
haematologica | 2021; 106(9)
2409