Blood Test of Circulating Cell-Free DNA Could Flag Most Stubborn B-Cell Lymphoma

The epigenetic signals in circulating cell-free DNA (cfDNA) in patients diagnosed with diffuse large B-cell lymphoma (DLBCL) could predict which cases are the most likely to recur, a team of scientists reported in the journal Blood Advances this week.

The 29-gene weighted prognostic score is based on the association between the demethylation signals of 5-hydroxymethylcytosinces (5hmC) and gene activation in the DNA roaming through the patients’ blood, the investigators wrote. 

“Our findings suggest that the 5hmC signatures in cfDNA at the time of diagnosis are associated with clinical outcomes and may provide a novel minimally invasive prognostic approach for DLBCL,” concluded the authors, led by personnel from the University of Chicago.

Between 20% and 40% of patients with DLBCL, the most common type of non-Hodgkin’s lymphoma, have a recurrence of the disease after the first round of treatment. 

The new test looks at 48 patients assessed at the University of Chicago Medical Center, between 2010 and 2013, and followed through the end of 2017. The median age of the group was 58 years of age (range from 24 to 82 years of age). Of the patients, 63% were males, and 50% were stage 1/2. 

The team used the 5hmC-Seal chemical labeling technique to assess event-free survival (EFS) and overall survival (OS), they wrote. 

The libraries of genes were constructed through polymerase chain reaction (PCR) and sequenced on an Illumina NextSeq 500. 

The feature selection process was repeated 100 times and the panel was selected from 80% or greater frequency. The 5hmC profiles were cross-referenced with disease characteristics and development. The 214 potential genes were thus trimmed to a total of 29. 

The “wp-score” then proved to have predictive value, they concluded. 

“Compared with patients in the low-risk group (i.e., low wp-score), patients in the high-risk group had worse OS (log-rank P = .001) or worse EFS (log-rank P = .002),” the authors wrote. “Specifically, in the multivariate analysis controlling for age and sex, high-risk scores (wp-scores) were associated with poorer EFS (HR, 9.17; 95% CI; 2.01-41.89; P = .004) compared with low-risk scores.

“Moreover, the wp-scores remained significantly associated with EFS after additional adjustment for standard prognostic factors, suggesting that the wp-scores are an independent prognostic factor for DLBCL,” they further concluded. “Importantly, results for overall accuracy, sensitivity, and specificity showed that the wp-scores had an overall superior performance for predicting, at diagnosis, patients at risk for having a clinical event during the follow-up compared with standard clinical prognostic factors.”

“Our findings, if validated in a larger independent patient population, could impact the cure rate for DLBCL,” added Brian Chiu, PhD, lead author, clinical cancer epidemiologist at the University of Chicago, in a statement released by the school on the work. “By identifying those patients who are at high-risk of treatment failure, we can see who may benefit from individualized clinical management or earlier treatment with novel or targeted therapies.”  

References:

Cjiu, B, Zhang Z, You Q, et al. Prognostic implications of 5-hydroxymethylcytosines from circulating cell-free DNA in diffuse large B-cell lymphoma. Blood Advances. 2019;3(19):2790-2799. DOI 10.1182/ bloodadvances.2019000175.