Expression of JL1 in Burkitt lymphoma is associated with improved overall survival

Prognostic Stratification of Patients with Burkitt Lymphoma Using Serum β2-microglobulin Levels

Purpose

We aimed to investigate the prognostic value of serum β2-microglobulin for patients with Burkitt lymphoma (BL) and to propose a risk-stratifying classification system.

Materials and Methods

A prospective registry-based cohort study of BL patients treated with dose-intensive or effective dose-adjusted chemotherapies (n=81) was conducted. Survival outcomes were compared based on previously reported risk groups and/or serum β2-microglobulin levels. A risk-stratifying classification system incorporating serum β2-microglobulin levels was proposed and validated in an independent validation cohort (n=60).

Results

The median age was 47 years, and 57 patients (70.4%) were male. Patients with high serum β2-microglobulin levels (> 2 mg/L) had significantly worse progression-free survival (PFS) and overall survival (OS) (p < 0.01 for both). Serum β2-microglobulin levels further stratified patients in the low-risk and high-risk groups in terms of PFS (p=0.010 and p=0.044, respectively) and OS (p=0.014 and p=0.026, respectively). Multivariate analyses revealed that a high serum β2-microglobulin level (> 2 mg/L) was independently associated with a shorter PFS (hazards ratio [HR], 3.56; p=0.047) and OS (HR, 4.66; p=0.043). The new classification system incorporating the serum β2-microglobulin level allowed the stratification of patients into three distinct risk subgroups with 5-year OS rates of 100%, 89.5%, and 62.5%. In an independent cohort of BL, the system was validated by stratifying patients with different survival outcomes.

Conclusion

Serum β2-microglobulin level is an independent prognostic factor for BL patients. The proposed β2-microglobulin–based classification system could stratify patients with distinct survival outcomes, which may help define appropriate treatment approaches for individual patients.

JL1 Antigen Expression on Bone Marrow Lymphoma Cells from Patients With Non-Hodgkin Lymphoma

Background

JL1, a CD43 epitope and mucin family cell surface glycoprotein, is expressed on leukemic cells. An anti-JL1 antibody combined with a toxic substance can have targeted therapeutic effects against JL1-positive leukemia; however, JL1 expression on bone marrow (BM) lymphoma cells has not been assessed using flow cytometry. We investigated JL1 expression on BM lymphoma cells from patients with non-Hodgkin lymphoma (NHL) to assess the potential of JL1 as a therapeutic target.

Methods

Patients with BM involvement of mature B-cell (N=44) or T- and natural killer (NK)-cell (N=4) lymphomas were enrolled from May 2015 to September 2016. JL1 expression on BM lymphoma cells was investigated using flow cytometry. Clinical, pathological, and cytogenetic characteristics, and treatment responses were compared according to JL1 expression status.

Results

Of the patients with NHL and BM involvement, 37.5% (18/48) were JL1-positive. Among mature B-cell lymphomas, 100%, 38.9%, 33.3%, 100%, and 25.0% of Burkitt lymphomas, diffuse large B-cell leukemias, mantle cell leukemias, Waldenstrom macroglobulinemia, and other B-cell lymphomas, respectively, were JL1-positive. Three mature T- and NK-cell NHLs were JL1-positive. JL1 expression was associated with age (P=0.045), complete response (P=0.004), and BM involvement at follow-up (P=0.017), but not with sex, performance status, the B symptoms, packed marrow pattern, cytogenetic abnormalities, or survival.

Conclusions

JL1 positivity was associated with superior complete response and less BM involvement in NHL following chemotherapy.