MATADOR: A prospective, randomised, phase III biomarker trial in breast cancer patients

A prospective, randomised, phase III biomarker trial (ISRCTN61893718) that run in 29 hospitals in the Netherlands. 664 Patients with an indication for adjuvant chemotherapy and a pT1-3, pN0-3 tumour were randomised 1:1 to 6 cycles of doxorubicin 60 mg/m2 and cyclophosphamide 600 mg/m2 every 2 weeks [dose dense (dd) AC] or docetaxel 75 mg/m2, doxorubicin 50 mg/m2, and cyclophosphamide 500 mg/m2 every 3 weeks (docetaxel-doxorubicin-cyclophosphamide; TAC) by means of the automated ALEA system (FormsVision BV) using Pocock minimization technique. Randomization was performed centrally at the Netherlands Cancer Institute. G-CSF (pegfilgrastim) was given to all patients. Radiotherapy and endocrine therapy were given according to the contemporary Dutch guidelines.

Formalin-fixed paraffin-embedded (FFPE) material was collected between 2004 and 2012. RNA was isolated from FFPE tissue with a tumor cell percentage of at least 40% using the AllPrep DNA/RNA Mini Kit according to the manufacturer's instructions (Qiagen). Quantification and purity were measured using the NanoDrop 2,000 spectrophotometer and the 2,100 Bioanalyzer (Agilent Technologies). Libraries of cDNA were constructed with the TruSeq RNA Access Library Prep Kit (Illumina) and single-end sequenced using the HiSeq 2,500 (Illumina). Bulk mRNA sequencing data were analyzed using the RSEM package and the reads were aligned to the hg38 reference genome using STAR with default parameters.

The immunohistochemistry biomarkers are describe in Opdam TheBreast 2026 with 10year follow-up (data till 2025). Immunohistochemistry was performed on a BenchMark Ultra autostainer (Ventana Medical Systems) for:
ER Roche Diagnostics 5278406001
PR Roche Diagnostics 5278392001
HER2 Roche Diagnostics 5278368001
AR Cell Marque clone SP107
Ki67 Dako #M7240 clone MIB-1
ABCB1 Cell signal 13978 clone E1Y7S
BCL2 Dako M0887 clone 124
GSTP1 Abnova MAB9663 clone LW29
MAPT USBiological 2B2.100 T1029
Thioredoxin Cell signaling cs2429_c63c6
TUBB Santa Cruz 5274 clone D-10
TUBB3 Abcam14545 TUJ1
Cyclin D1 RM-9104-S Thermo clone SP4
EZH2 Leica Clone 6A10 EZH2-L-CE
pH2AX Cell Signaling #2577
P53 M7001 Dako clone DO-7