Molecular features encoded in the ctDNA reveal heterogeneity and predict outcome in high-risk aggressive B-cell lymphoma.

Inadequate molecular and clinical stratification of the patients with high-risk diffuse large B-cell lymphoma (DLBCL) is a clinical challenge hampering the establishment of personalized therapeutic options. We studied the translational significance of liquid biopsy in a uniformly treated trial cohort. Pretreatment circulating tumor DNA (ctDNA) revealed hidden clinical and biological heterogeneity, and high ctDNA burden determined increased risk of relapse and death independently of conventional risk factors. Genomic dissection of pretreatment ctDNA revealed translationally relevant phenotypic, molecular, and prognostic information that extended beyond diagnostic tissue biopsies. During therapy, chemorefractory lymphomas exhibited diverging ctDNA kinetics, whereas end-of-therapy negativity for minimal residual disease (MRD) characterized cured patients and resolved clinical enigmas, including false residual PET positivity. Furthermore, we discovered fragmentation disparities in the cell-free DNA that characterize lymphoma-derived ctDNA and, as a proof-of-concept for their clinical application, used machine learning to show that end-of-therapy fragmentation patterns predict outcome. Altogether, we have discovered novel molecular determinants in the liquid biopsy that can noninvasively guide treatment decisions.

Combining MYC, BCL2 and TP53 gene and protein expression alterations improves risk stratification in diffuse large B-cell lymphoma.

Translocations affecting both MYC and BCL2 are associated with a poor prognosis in diffuse large B-cell lymphomas. We have examined genetic aberrations combined with analyses of protein expression of respective gene products. Fluorescence in situ hybridization (FISH) for translocations of BCL2 and MYC and del17p13 was performed. Immunohistochemistry analyses included BCL2, MYC and TP53 protein expression. Sixty-seven patients with high-risk DLBCL participating in a prospective multicenter study were included. Six patients with simultaneous translocations of BCL2 and MYC had impaired overall (OS) (p = 0.009) and progression-free survival (PFS) (p = 0.009). Six patients with high coexpression of MYC and BCL2 proteins also had impaired OS (p = 0.004) and PFS (p = 0.002). Combining these groups identified nine patients with impaired OS (p = 0.004) and PFS (p = 0.005). Sixteen patients had double-hit translocation or protein expression and/or del17p13 and/or high TP53. This combined endpoint was associated with impaired OS (p = 0.008) and PFS (p = 0.036), and identified 70% of all deaths.

Prognostic influence of macrophages in patients with diffuse large B-cell lymphoma: a correlative study from a Nordic phase II trial.

The prognostic impact of the tumor microenvironment in diffuse large B-cell lymphoma has not been systematically assessed. We analyzed mRNA and antigen expression of monocytes, macrophages, lymphocytes, dendritic and natural killer cells in pretreatment tumor samples of patients with high-risk diffuse large B-cell lymphoma using gene expression microarray and immunohistochemistry. The patients were treated in a Nordic phase II study with dose-dense chemoimmunotherapy and central nervous system prophylaxis. Of the studied markers for non-malignant inflammatory cells, CD68 expression and CD68(+) macrophage counts correlated with favorable outcome. Five-year progression-free survival rates were 83% and 43% for the patients with high and low CD68 mRNA levels, respectively (P=0.007), while overall survival rates were 83% and 64%, respectively (P=ns). The patients with high CD68(+) macrophage counts had better 5-year progression-free survival (74% versus 40%; P=0.003) and overall survival (90% versus 60%; P=0.009) than the patients with low macrophage counts. Low CD68(+) macrophage count retained its prognostic impact on overall survival with age-adjusted International Prognostic Index [RR=5.0 (95% CI 1.024-19.088); P=0.017]. The findings were validated in three independent cohorts of patients treated with chemoimmunotherapy. In contrast, in patients treated with chemotherapy, high CD68(+) macrophage count was associated with poor progression-free survival (40% versus 72%; P=0.021) and overall survival (39% versus 72%; P=0.015). Together, the data suggest that macrophages exhibit a dual, treatment-specific role in diffuse large B-cell lymphoma. For the patients treated with chemoimmunotherapy, high pretreatment CD68 mRNA levels and CD68(+) macrophage numbers predict a favorable outcome.

Karyotyping of diffuse large B-cell lymphomas: loss of 17p is associated with poor patient outcome.

BACKGROUND: Cytogenetic studies of patients with diffuse large B-cell lymphoma (DLBCL) have revealed a large spectrum of chromosomal abnormalities, some of which may be clinically relevant. We wanted to evaluate possible associations between commonly acquired chromosome aberrations and prognosis in a large cohort of patients. METHODS: All patients with DLBCL treated at our center during 1999-2010 with an abnormal G-banding karyotype determined on cells short-term cultured from diagnostic biopsies were included. Detailed information on staging, treatment, and outcome was available for all patients. RESULTS: Of the 110 patients available for analysis, there were 48 deaths and 27 relapses after a median follow-up of 4.5 yr. Eleven different chromosomal abnormalities were detected in more than ten percent of patients. Of those, only loss of 17p, including the TP53 tumor suppressor gene, was significantly associated with inferior long-term prognosis. Five year overall and progression-free survival frequencies were 32% and 27% for patients with loss of 17p and 67% and 59% in patients without this abnormality. CONCLUSION: In a relatively large cohort of patients with DLBCL analyzed by chromosome banding, loss of 17p was the only chromosomal abnormality associated with inferior survival in uni- and multivariate analysis.