Heparanase (HPSE) promotes cancer pain in mice by interacting with Syndecan-1 (SDC1). (A) The expression of SDC1 was detected by western blot after SST0001 treatment. (B) SDC1 in tumor tissues was detected by IHC (200×, scale bar = 100 μm). (C) The expression of SDC1 was detected by qRT-PCR after the treatment of Ad-SDC1 and/or SST0001. (D) Paw thickness. (E) Mechanical allodynia. (F) Cold response. (G) Spontaneous pain. (H–J) The content of TNF-α, NF-κB, IL-6, IL-1β, and PD-L1 were determined by ELISA assay. (K) PGE2 expression was detected by qRT-PCR. **P < 0.01 versus control. ##P < 0.01 versus model. $P < 0.05, $$P < 0.01 versus Model + SST0001. The error bars indicate mean ± standard deviation. IHC: immunohistochemical, qRT-PCR: quantitative real-time polymerase chain reaction, TNF-α: tumor necrosis factor-alpha, NF-κB: nuclear factor-κB, IL: interleukin, PD-L1: programmed death-ligand 1, PGE2: prostaglandin E2, ELISA: enzyme-linked immunosorbent assay, IOD: integrated optical density.