Clinicopathologic implication of PD-L1 and phosphorylated STAT3 expression in diffuse large B cell lymphoma.
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ABSTRACT: BACKGROUND:Antitumor immune response of programmed cell death ligand (PD-L1) has shown clinical value not only in Hodgkin lymphoma and EBV-associated lymphomas but also in EBV-negative diffuse large B cell lymphoma (DLBCL) of non-germinal center B cell-like (non-GCB) subtype. Signal transducer and activator of transcription 3 (STAT3) is known to induce PD-L1 in immune cells and its activated form, phosphorylated STAT3 (pSTAT3), is also frequently expressed in non-GCB DLBCL. Herein, we investigated associations between PD-L1 expression/gene alteration, pSTAT3 expression and clinicopathologic variables in EBV-negative DLBCL. METHODS:In 107 cases of DLBCLs with non-GCB subtype (67%; 72/107), GCB subtype (25%; 27/107) and unclassifiable cases (8%; 8/107), we performed PD-L1 and pSTAT3 immunohistochemistry and fluorescence in situ hybridization for PD-L1 gene translocation and copy number gain/amplification. RESULTS:PD-L1 was expressed in tumor cells (PD-L1t) in 21% (23/107; 30% cutoff), immune cells (PD-L1i) in 36% (38/107; 20% cutoff), and pSTAT3 in tumor nuclei in 41% (44/107; 40% cutoff). PD-L1 gene alteration was observed in 10% (10/102) including translocation in 6% (6/102) and copy number gain/amplification in 4% (4/102). Non-GCB subtype was associated with PD-L1t and pSTAT3 (p?=?0.006 and p?=?0.042), and tended to have PD-L1 gene alteration (p?=?0.058). Tumoral PD-L1 expression without gene alteration (PD-L1t+ GA-) correlated with pSTAT3-positive tumor cell proportions (%) (p?=?0.033). In survival analysis, pSTAT3 expression independently predicted shorter PFS in total cohort (p?=?0.017) and R-CHOP-treated group (p?=?0.007), and in pSTAT3-negative R-CHOP-treated subset, PD-L1 expression in immune cells (PD-L1i) correlated with shorter PFS (p?=?0.042). CONCLUSIONS:Gene alteration and protein expression of PD-L1 and pSTAT3 expression were closely related in DLBCL and constituted features of non-GCB subtype. In addition to known clinical significance of pSTAT3, immune cell expression of PD-L1 (PD-L1i) had also clinical value in pSTAT3-dependent manner. These findings may provide an insight into immunotherapeutic strategy and risk stratification in DLBCL patients.
SUBMITTER: Kwon HJ
PROVIDER: S-EPMC6245852 | biostudies-literature | 2018 Nov
REPOSITORIES: biostudies-literature
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