[Thymidine kinase: a serum marker in clinical medicine]

The need for new seric markers of tumoral or viral activity to enable an early diagnosis or staging has brought about a proliferation of research in new markers. The deoxi-thymidine-kinase (DTK) is an enzyme of DNA synthesis during cellular proliferation. We review the literature, concluding that DTK is a good seric marker in some neoplasias and some viral diseases because of its specificity, low cost and rapid testing in multiple samples.