MASTL is a potential poor prognostic indicator in ER+ breast cancer.

OBJECTIVE In this study, we aimed to explore prognostic value of MASTL (microtubule-associated serine/threonine kinase-like) in breast cancer patients on the basis of ER status and molecular subtypes. MATERIALS AND METHODS The raw microarray data (GDS5666) of 4T1 derived bone-aggressive explant and primary tumor explant were reanalyzed to identify the dysregulated genes. To pool previous annotated genomic data that assessed the association between MASTL expression and metastatic relapse (MR) risk, MR-free survival, any event (AE, defined as any relapse or death) risk, and AE-free survival in breast cancer patients, a meta-analysis was performed by bc-GenExMiner 4.0. RESULTS MASTL is a significantly upregulated gene in 4T1 bone-aggressive explant compared to primary tumor explant. Univariate Cox analysis showed that high MASTL expression is associated with a higher risk of MR (HR: 1.43, 95%CI: 1.28-1.60; p<0.001) and a higher risk of AE (HR: 1.27, 95%CI: 1.18-1.37; p<0.001) in ER+ breast cancer. Also, high MASTL expression also predicts a worse MR-free survival (HR: 1.74, 95%CI: 1.40-2.17; p<0.001) and a worse AE-free survival (HR: 1.42, 95%CI: 1.23-1.63; p<0.001) in ER+ breast cancer. However, the associations were not observed in ER- patients. The following NPI adjusted analyses confirmed the results of univariate Cox analysis. In Single Sample Predictors (SSPs) and Subtype Clustering Models (SCMs) subtypes, high MASTL expression is associated with increased risk of AE and predicts a poor AE-free survival in ER+ subgroups. CONCLUSIONS MASTL might be a valuable indicator of MR risk and AE risk in ER+ patients, but not in ER- patients.