Frequent PD-L1 expression in primary and metastatic penile squamous cell carcinoma: potential opportunities for immunotherapeutic approaches.


Despite aggressive multimodal therapy, locally advanced and/or metastatic penile squamous cell carcinoma (SqCC) is associated with significant morbidity and mortality, indicating a need for new therapeutic options. Given the emerging clinical utility of immunotherapeutics, we sought to assess the incidence and potential clinical significance of PD-L1 expression in penile SqCC.

Using an anti-PD-L1 primary antibody (clone 5H1), immunohistochemistry was carried out on whole tumor sections from 37 patients with penile SqCC treated at our institution between 2005 and 2013. PD-L1-positive tumors were defined as those with membranous staining in ≥5% of tumor cells. Association between PD-L1 expression and clinicopathologic parameters was examined using Fisher's exact test. Correlation between PD-L1 expression in primary tumors and matched metastases was assessed using the Spearman rank correlation coefficient (ρ). The difference in cancer-specific mortality between PD-L1-positive and -negative groups was examined using the log-rank test.

Twenty-three (62.2%) of 37 primary tumors were positive for PD-L1 expression, and there was strong positive correlation of PD-L1 expression in primary and metastatic samples (ρ = 0.72; 0.032 < P < 0.036). Primary tumor PD-L1 expression was significantly associated with usual type histology (P = 0.040) and regional lymph node metastasis (P = 0.024), as well as decreased cancer-specific survival (P = 0.011).

The majority of primary penile SqCC tumors express PD-L1, which is associated with high-risk clinicopathologic features and poor clinical outcome. These data provide a rational basis for further investigation of anti-PD-1 and anti-PD-L1 immunotherapeutics in patients with advanced penile SqCC.

  • Alva A
  • Cao X
  • Chinnaiyan AM
  • Feng FY
  • Fields KL
  • Jiang H
  • Liu TY
  • Magers MJ
  • McDaniel AS
  • Mehra R
  • Montgomery JS
  • Morgan TM
  • Palapattu GS
  • Siddiqui J
  • Skala SL
  • Spratt DE
  • Tomlins SA
  • Udager AM
  • Weizer AZ
PubMed ID
Appears In
Ann Oncol, 2016, 27 (9)