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Fig. 3 | Breast Cancer Research

Fig. 3

From: Serum thymidine kinase 1 activity as a pharmacodynamic marker of cyclin-dependent kinase 4/6 inhibition in patients with early-stage breast cancer receiving neoadjuvant palbociclib

Fig. 3

Box plots of serum thymidine kinase 1 (TK1), tumor Ki-67, and tumor TK1 messenger RNA (mRNA) levels by time point for patients enrolled in the NeoPalAna trial. The comparison between time points was done using the Wilcoxon signed-rank test. Similar to tumor Ki-67, serum TK activity was significantly lower on cycle 1, day 15 (C1D15), 2 weeks after adding palbociclib. However, unlike tumor Ki-67 and TK1 mRNA levels, serum TK1 activity did not differ between baseline (C0D1) and cycle 1, day 1 (C1D1), with anastrozole alone. Similar to tumor Ki-67, a significant rebound increase in serum TK1 level was observed at the time of surgery with palbociclib withdrawal, which was suppressed when an additional cycle (cycle 5) of palbociclib was added before surgery. Tumor TK1 mRNA change at surgery time points did not reach statistical significance. *** p < 0.001, * p < 0.05

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