PG545 (pixatimod, INN) is a small-molecule immunomodulatory agent with strong anti-heparanase activity12–14 that has been demonstrated to potently inhibit tumour-associated macrophages (TAM) in preclinical cancer models.15,16 Because heparanase plays a key role in the molecular decision-making that guides the cancer-promoting actions of TAM in pancreatic carcinoma,17 inhibition of this protein may be responsible for the inhibition of TAM in those studies. The gene discussed is HPSE; the disease is exocrine pancreatic carcinoma.