The coexpression of platelet-derived growth factor (PDGF) and its receptor (PDGFR) is frequently detected in a variety of tumours including malignant glioma (Maxwell et al, 1990; Hermanson et al, 1992; Guha et al, 1995), lung cancer (Antoniades et al, 1992), and sarcoma (Smits et al, 1992), suggesting the existence of PDGF autocrine loop. The gene discussed is PDGFRB; the disease is malignant glioma.