Plasma thymidine kinase-1 activity predicts outcome in patients with hormone receptor positive and HER2 negative metastatic breast cancer treated with endocrine therapy.

Plasma thymidine kinase-1 activity predicts outcome in patients with hormone receptor positive and HER2 negative metastatic breast cancer treated with endocrine therapy. Oncotarget. 2018 Mar 27;9(23):16389-16399 Authors: Bonechi M, Galardi F, Biagioni C, De Luca F, Bergqvist M, Neumüller M, Guarducci C, Boccalini G, Gabellini S, Migliaccio I, Di Leo A, Pestrin M, Malorni L Abstract The aim of this study was to investigate if thymidine kinase-1 (TK1), a well-known proliferation marker, could represent a valid circulating biomarker to identify hormone receptor positive (HR+)/HER2 negative (HER2neg) metastatic breast cancer (MBC) patients most likely to benefit from endocrine therapy (ET). We used the DiviTum™ assay to analyze TK1 activity in cell lysates of three HR+/HER2neg BC cell lines and in plasma of 31 HR+/HER2neg MBC patients receiving ET. Blood samples were collected at treatment initiation, after one month and at disease progression. CTCs count and ESR1/PIK3CA mutations in circulating tumor DNA were performed and correlated with TK1 activity. TK1 activity was reduced in the two endocrine-sensitive cell lines after 2 days of treatment. In patients, high baseline TK1 activity correlated with CTCs positivity (p-value=0.014). Patients with low baseline levels of TK1 activity had a significantly better PFS compared to those with high baseline TK1 activity (p-value=0.012). Patients with an early drop of TK1 activity after one mon...
Source: Oncotarget - Category: Cancer & Oncology Tags: Oncotarget Source Type: research