Programmed death-ligand 1 (PD-L1) expression can predict event-free survival in diffuse large B-cell lymphoma (DLBCL) cases leading to poor prognosis, a new study published in The International Journal of Biological Markers revealed.

The study found a significant association of PD-L1 expression with the elevated pre-treatment LDH level but not with age, gender, stage, or the DLBCL subtype. Moreover, the median event-free survival (EFS) was higher in the PD-L1 negative subjects, suggesting that EFS might have a prognostic value for patients with DLBCL. 

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Lymphoma is a type of cancer that begins in the lymphatic system and can be classified into two types: Hodgkin lymphoma and non-Hodgkin lymphoma (NHL). The most prevalent aggressive subtype of NHL is DLBCL, the authors noted.

The expression of PD-L1 is reported to be upregulated in tumors, with the degree of PD-L1 expression having a prognostic value in cancer patients, the researchers wrote. A recent study has shown that PD-L1 expression may vary based on the population’s genetic makeup. The current study examined PD-L1 expression in Arab Jordanians with DLBCL, as it has not been investigated in previous studies, the study authors continued.

The study evaluated the frequency of PD-L1 expression in DLBCL Jordanian Arabs. The research team included 75 Arab Jordanian patients with DLBCL who were cared for at the King Hussein Cancer Center from 2015 to 2018. They assessed the expression of PD-L1 in tumor tissue by immunohistochemistry using the antihuman PD-L1 (Clone 22C3) monoclonal antibody. Moreover, the researchers studied the correlation between age, gender, clinical stage, LDH level before treatment, overall and event-free survival, tumor location, and therapy response using the PD-L1 expression. 

Study results suggested that the tumor proportion score (TPS) was ≥1% in 16 of the 69 (23.2%) patients with DLBCL, while the combined positive score (CPS) at a cut-off of ≥20 was found in 23 (33.3%) patients. Moreover, no significant difference was found in PD-L1 expression between the germinal center B-cell-like (GCB) and the nonGCB subtypes. Additionally, no differences in PD-L1 expression were observed between different age groups, genders, tumor locations, clinical stages, and patient’s responses to therapy. 

The results also revealed a significant elevation of base-line lactate dehydrogenase in patients with PD-L1 CPS ≥20. Furthermore, there was no considerable difference in the OS between the PD-L1-positive and -negative groups. On the contrary, the median EFS was found to be greater in either the PD-L1 TPS or the CPS negative groups at 107 months compared to the 54 months in the PD-L1 positive group of the 2 categories. PD-L1 expression can quickly and accurately predict EFS and poor prognosis in patients with DLBCL.

Reference

Al-Khateeb E, Abbas MA, Khader MB, Sughayer MA. Programmed death-ligand 1 expression in diffuse large B-cell lymphoma is associated with poor prognosisThe International Journal of Biological Markers. Published online January 9, 2023.