Prognostic value of the 6-gene OncoMasTR test in hormone receptor-positive HER2-negative early-stage breast cancer: Comparative analysis with standard clinicopathological factors

Select gene mutations associated with survival outcomes in ER-positive ERBB2-negative early-stage invasive breast cancer: A single-institutional tissue bank study

INTRODUCTION

The prognostic capability of targeted sequencing of primary tumors in patients with estrogen receptor-positive, human epidermal growth factor receptor-2-negative early-stage invasive breast cancer (EBC) in a real-world setting is uncertain. Therefore, we aimed to determine the correlation between a 22-gene mutational profile and long-term survival outcomes in patients with ER+/ERBB2- EBC.

PATIENTS AND METHODS

A total of 73 women diagnosed with ER+/ERBB2- EBC between January 10, 2004, and June 2, 2008, were followed up until December 31, 2022. Univariate and multivariate Cox models were constructed to plot the relapse-free survival (RFS) and overall survival (OS). The log-rank test derived p-value was obtained. For external validation, we performed a survival analysis of 1163 comparable patients retrieved from the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) dataset.

RESULTS

At follow-up, 16 (21.9%) patients had relapsed, while 21 (nearly 29%) harbored mutant genes. Thirty-three missense mutations were detected in 14 genes. The median ages were 51 and 46 years in patients with and without mutations, respectively. Patients with any mutation had a 1.85-fold higher risk of relapse (hazard ratio [HR]: 1.85, 95% confidence interval [CI]: 0.60-5.69) compared to those without any mutation. Patients who harbored any of the six genes (MAP2K4, FGFR3, APC, KIT, RB1, and PTEN) had a nearly 6-fold increase in the risk of relapse (HR: 5.82, 95% CI: 1.31-18.56; p = 0.0069). Multivariate Cox models revealed that the adjusted HR for RFS and OS were 6.67 (95% CI: 1.32-27.57) and 8.31 (p = 0.0443), respectively. METABRIC analysis also demonstrated a trend to significantly worse RFS (p = 0.0576) in the subcohort grouped by having a mutation in any of the six genes.

CONCLUSIONS

Our single-institution tissue bank study of Taiwanese women with ER+/ERBB2- EBC suggests that a novel combination of six gene mutations might have prognostic capability for survival outcomes.

Microfluidic Isolation of Disseminated Tumor Cells from the Bone Marrow of Breast Cancer Patients

Disseminated tumor cells (DTCs) in the bone marrow (BM) of breast cancer (BC) patients are putative precursors of metastatic disease, and their presence is associated with an adverse clinical outcome. To achieve the personalization of therapy on a clinical routine level, the characterization of DTCs and in vitro drug testing on DTCs are of great interest. Therefore, biobanking methods, as well as novel approaches to DTC isolation, need to be developed. In this study, we established a protocol for the biobanking of BM samples and evaluated a microfluidic-based separation system (Parsortix®) for the enrichment of cryopreserved DTCs. We were able to successfully isolate viable DTCs after the prior cryopreservation of BM samples. We calculated a significant increase of up to 90-fold in harvested DTCs with the proposed method compared to the current standard techniques, opening up new analysis possibilities for DTCs. Our advanced method further presents options for 3D DTC cultures, enabling the individualized testing of targeted therapies for BC patients. In conclusion, we present a novel approach for DTC enrichment, with possibilities for future clinical implications.