title: Serum levels of soluble programmed cell death ligand 1 as a prognostic factor on the first-line treatment of metastatic or recurrent gastric cancer.
abstract: OBJECTIVE
  Immune checkpoint molecules are key targets for the treatment of various malignancies. Due to the heterogeneity of advanced gastric cancer (GC), the role of programmed cell death ligand 1 (PD-L1) expression as a tumor biomarker remains controversial. In this study, the prognostic value of soluble PD-L1 (sPD-L1) levels in serum samples was assessed in patients with metastatic GC.
  
  
  METHODS
  All patients received first-line treatment with fluoropyrimidine and platinum chemotherapy, and trastuzumab was added for HER2-positive patients. Serum levels of sPD-L1 were measured by enzyme-linked immunosorbent assay.
  
  
  RESULTS
  Among 75 metastatic GC patients, the median serum sPD-L1 level was 0.704 ng/ml (range <0.156-3.214). Serum sPD-L1 was significantly higher in patients with a high versus a low white blood cell count at baseline. When the cutoff value was set as the median, multivariate analyses showed that high sPD-L1 levels were associated with worse overall survival compared with low sPD-L1 levels (HR 2.218, 95 % CI 1.139-4.320, P = 0.019). Regardless of HER2 status, overall survival tended to be shorter in patients with high sPD-L1 compared with low sPD-L1. There was no significant association between sPD-L1 level and progression-free survival on the first-line treatment of metastatic GC.
  
  
  CONCLUSIONS
  High serum levels of sPD-L1 correlated with worse overall survival on the first-line chemotherapy in metastatic GC patients.
authors.affiliation: Gastrointestinal Medical Oncology Division, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan. naoki19800623@gmail.com.
authors.forename: Naoki
authors.initials: N
authors.lastname: Takahashi
authors.affiliation: Gastrointestinal Medical Oncology Division, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Iwasa
authors.affiliation: Gastrointestinal Medical Oncology Division, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Sasaki
authors.affiliation: Gastrointestinal Medical Oncology Division, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Shoji
authors.affiliation: Gastrointestinal Medical Oncology Division, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Honma
authors.affiliation: Gastrointestinal Medical Oncology Division, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan.
authors.forename: Atsuo
authors.initials: A
authors.lastname: Takashima
authors.affiliation: Gastrointestinal Medical Oncology Division, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan.
authors.forename: Natsuko Tsuda
authors.initials: NT
authors.lastname: Okita
authors.affiliation: Gastrointestinal Medical Oncology Division, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Kato
authors.affiliation: Gastrointestinal Medical Oncology Division, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Hamaguchi
authors.affiliation: Gastrointestinal Medical Oncology Division, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan.
authors.forename: Yasuhide
authors.initials: Y
authors.lastname: Yamada
mesh_terms: D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D060890:B7-H1 Antigen / Q000097:blood*; D014408:Biomarkers, Tumor / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local; D013274:Stomach Neoplasms / Q000097:blood / Q000188:drug therapy / Q000473:pathology*
chemical_list: D060890:B7-H1 Antigen; D014408:Biomarkers, Tumor; C423236:CD274 protein, human
keywords: Gastric cancer; PD-L1; Prognostic factor; Serum