Co-expression of thymidine kinase and cathepsin D in 200 primary breast carcinomas.

We assayed thymidine kinase (TK) and cathepsin D (Cath-D) in 200 breast carcinomas and we found that they were significantly correlated. This correlation was present in lymph node positive tumours, in G2 and G3, in T1 and in invasive ductal carcinomas. In addition, TK and Cath-D did not correlate with oestrogen receptor (ER) and progesterone receptor (PgR) status. We conclude that the relationship between Cath-D and TK may indicate a tumour population of high proliferation activity and invasiveness potential, related to a more aggressive phenotype, whose identification may be useful in defining prognosis.