PGP and neoplasm: Table 1 summarises these correlations. Tumours with strong expression of Pgp were more frequently observed in patients with AFP levels <1000 ng ml−1 (P=0.026). Tumours with strong expression of MRP1 correlated with LDH levels >1.5 upper normal threshold (P=0.014). No association could be identified for BCRP. Tumours with strong or intermediate expression of LRP associated with β-hCG levels >5000 IU/l−1 (P=0.003) and stage IV (P=0.029) according to the Royal Marsden Hospital (RMH) Classification (Peckham et al, 1979).