Clinical value of thymidine kinase and tissue polypeptide specific antigen in breast cancer

Thymidine kinase (TK) and tissue polypeptide specific antigen (TPS) were determined in breast cancer (BC) patients (n = 83), normal healthy women (n = 30) and 18 women with different benign mastopathies. Mean serum levels of TK and TPS in BC patients showed significant increases from their corresponding levels in healthy women and those with benign breast diseases. Diagnostic sensitivity of TK and TPS was 47% and 58% respectively at the selected cut-off values 8 U/L for TK and 110 U/L for TPS (96% specificity). Pre-operative serum levels of TK and TPS showed significant correlation with the stage of disease and with other classical prognostic factors; clinical stage, tumour size, lymph node involvement and distant metastasis. Nineteen BC patients were followed-up by serial monthly measurements of TK and TPS (4-10 samples). Both markers seemed to be valuable in monitoring drug efficacy. TK and TPS were able to detect systemic recurrence before clinical diagnosis (average 2 months lead time). TPS was greatly affected by liver diseases.