Increased infiltration of CCR4-positive regulatory T cells in prostate cancer tissue is associated with a poor prognosis

Masahito Watanabe, Kent Kanao, Susumu Suzuki, Hiroyuki Muramatsu, Singo Morinaga, Keishi Kajikawa, Ikuo Kobayashi, Genya Nishikawa, Yoshiharu Kato, Kenji Zannami, Kogenta Nakamura, Toyonori Tsuzuki, Kazuhiro Yoshikawa, Ryuzo Ueda, Makoto Sumitomo

Research output: Contribution to journalArticlepeer-review

39 Citations (Scopus)

Abstract

Background: Regulatory T cells (Tregs) play important roles in the suppression of immune responses, including antitumor immune responses. C-C chemokine receptor 4 (CCR4) is highly expressed on effector Tregs, and anti-CCR4 antibody is attracting attention as a novel immunotherapeutic agent for solid tumors. This study aimed to evaluate the expression of CCR4-positive Tregs (CCR4+Tregs) in prostate cancer and estimate the clinical potential of CCR4-targeting therapy for prostate cancer. Methods: A total of 15 radical prostatectomy (RP) specimens and 60 biopsy specimens from individuals diagnosed with prostate cancer were analyzed to evaluate the infiltration of CCR4+Tregs in prostate cancer. The relationships between the number of CCR4+Tregs and clinical parameters were investigated in RP and biopsy specimens. Moreover, the total number of Tregs, CCR4+Tregs, and T cells and the ratio of CCR4+Tregs to Tregs and T cells in biopsy specimens were compared between patients with poor prognosis who progressed to castration-resistant prostate cancer (CRPC) within 12 months (n = 13) and those with good prognosis who were stable with hormone-sensitive prostate cancer over 12 months (n = 47). Furthermore, biopsy specimens were divided into two groups: low and high CCR4+Treg expression groups and the prognosis was compared between them. Results: There was a higher expression of CCR4+Tregs in RP specimens with a higher (≥8) Gleason score than in those with a lower (<8) Gleason score (P =.041). In biopsy specimens, 65.9% Tregs were positive for CCR4. The number of CCR4+Tregs positively correlated with clinical stage (P <.001) and Gleason score (P =.006). The total number of Tregs and CCR4+Tregs significantly increased in the poor prognosis group compared with that in the good prognosis group (P =.024 and.01, respectively). Furthermore, patients with lower CCR4+Treg expression levels showed a significantly longer time to progression to CRPC (not reached vs 27.3 months; P <.001) and median survival time (not reached vs 69.0 months; P =.014) than those with higher expression levels. Conclusions: CCR4+Tregs are highly infiltrated in the prostate tissue of patients with poor prognosis with potential to progress to CRPC. Furthermore, the degree of infiltration of CCR4+Tregs is related to the prognosis of prostate cancer.

Original languageEnglish
Pages (from-to)1658-1665
Number of pages8
JournalProstate
Volume79
Issue number14
DOIs
Publication statusPublished - 10-2019

All Science Journal Classification (ASJC) codes

  • Oncology
  • Urology

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