However, cell lines are homogeneous, while tumours are heterogeneous with unknown amounts of tumour, stroma and infiltrating cells, which can all contain considerable amounts of TP expression (Takahashi et al, 1996; Giatromanolaki et al, 1998; Matsumura et al, 1998; van Triest et al, 2000). Here, TYMP is linked to neoplasm.