Significance of programmed cell death-ligand 1 expression and its association with survival in patients with small cell lung cancer.
BACKGROUND
Programmed cell death 1 receptor-ligand interaction is a major pathway often hijacked by tumors to suppress immune control. The aim of this retrospective study was to investigate the prevalence and prognostic roles of programmed cell death -ligand 1 (PD-L1) expression in small cell lung cancer (SCLC).


METHODS
The expression of PD-L1 was evaluated by immunohistochemical analysis in 102 specimens of SCLC. Tumors with staining in over 5% of tumor cells were scored as positive for PD-L1 expression. Survival analysis was performed using the Kaplan-Meier method.


RESULTS
Expression of PD-L1 in tumor cells was observed in 71.6% (73 of 102) of SCLCs, and was significantly correlated with a limited disease (LD) stage. SCLC patients with PD-L1-positive tumors showed significantly longer overall survival (OS) than those with PD-L1-negative (median OS, 16.3 versus 7.3 months; p < 0.001, respectively). Multivariate analyses demonstrated that a good performance status, LD stage, and expression of PD-L1 were significantly predictive of better OS, independently of other factors. We found no relevance between PD-L1 expression and progression-free survival for first-line treatment in LD- and extensive disease-SCLC patients.


CONCLUSIONS
In patients with SCLC, expression of PD-L1 is positively correlated with a LD stage, and is independently predictive of a favorable outcome.
*Division of Respirology, Neurology, and Rheumatology, Department of Internal Medicine, Kurume University School of Medicine, Kurume, Fukuoka, Japan; and †Department of Diagnostic Pathology, Kurume University Hospital, Kurume, Fukuoka, Japan.
Hidenobu
H
Ishii
Koichi
K
Azuma
Akihiko
A
Kawahara
Kazuhiko
K
Yamada
Yohei
Y
Imamura
Takaaki
T
Tokito
Takashi
T
Kinoshita
Masayoshi
M
Kage
Tomoaki
T
Hoshino
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D060890:B7-H1 Antigen / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000378:metabolism*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007124:Immunoenzyme Techniques; D008175:Lung Neoplasms / Q000378:metabolism / Q000401:mortality / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D012189:Retrospective Studies; D055752:Small Cell Lung Carcinoma / Q000378:metabolism / Q000401:mortality / Q000556:secondary*; D015996:Survival Rate
D060890:B7-H1 Antigen; D014408:Biomarkers, Tumor; C423236:CD274 protein, human