Changes of thymidine kinase (TK) during adjuvant and palliative chemotherapy

Thymidine kinase is involved in nucleic acid synthesis and is, therefore, considered to be an important proliferation tumor marker. For this reason, we monitored this marker in the course of colorectal cancer chemotherapy. Materials and Methods: We examined thymidine kinase (TK) levels in 30 patients with colorectal cancer who underwent adjuvant or palliative chemotherapy (CHT schemes). The condition for being included in the study was a minimum of 3 cycles of chemotherapy. TK was always assessed with radio-receptor analysis, before and after every chemotherapy cycle, together with other tumor markers. Results: From the monitored tumor markers, only TK changed typically in the course of chemotherapy. In adjuvant chemotherapy, it was mostly low at the beginning of the cycle and its values usually increased considerably at the end. On the other hand, in palliative chemotherapy the dynamics of TK varied mainly depending on the effect of the therapy. Other tumor markers showed non-standard behavior and minimal correlation with TK changes. Conclusion: Thymidine kinase seems to be a suitable parameter for monitoring the effect of adjuvant and palliative chemotherapy in colorectal cancer.