Investigation of recurrence prediction ability of EndoPredict® using microarray data from fresh frozen tissues in ER-positive, HER2-negative breast cancer and indication expansion of EndoPredict® from microarray data from fresh-frozen to FFPE tissues.

BACKGROUND: EndoPredict® (EP) is a multigene assay to predict distant recurrence risk in luminal breast cancer. EP measures the expression of 12 genes in primary tumor by qRT-PCR from formalin-fixed paraffin-embedded (FFPE) tissues and calculates EP risk score that indicates the risk of distant recurrence. We evaluated the performance of EP in predicting distant recurrence risk using microarray data from fresh frozen (FF) tissues. We also examined the applicability of EP to microarray data from FFPE tissues. METHODS: We analyzed the publicly available data of 431 node-negative and 270 node-positive patients with luminal breast cancer who received endocrine therapy alone. We evaluated the prognostic value of EP using microarray data from FF tissues. Next, we created an algorithm to calculate EP risk score using microarray data from FFPE tissues. We examined the correlation coefficient of EP risk score and concordance rate of EP risk high/low using microarray data from FFPE/FF tissue pairs in a validation set of 39 patients. RESULTS: In 431 node-negative patients, the distant recurrence-free survival (DRFS) rate was significantly worse in those with high EP risk scores (P = 3.68 × 10-6, log-rank). The 5-year DRFS was 95.2% in those with low EP risk score. In the validation set, the correlation coefficient of EP risk score was 0.93 and the concordance rate of EP risk high/low was 91.7%. CONCLUSIONS: EP using microarray data from FF tissues was useful in predicting distant recurrence risk in luminal breast cancer, and EP might be utilized in microarray data from FFPE tissues.

Validation of late recurrence prediction by gene expression profiles and clinicopathological factors in estrogen receptor-positive breast cancer.

BACKGROUND: The mechanism of late recurrence (LR) of estrogen receptor (ER)-positive breast cancer remains unclear, as previous studies have separately investigated "gene expression profiles" and "clinicopathological factors." Thus, this study aimed to evaluate the predictive capability of LR by combining the two independent factors of gene expression profiles (42-gene classifier: 42GC) and clinicopathological factors (Clinical Treatment Score post-5 years: CTS5) in multiple large cohorts. METHODS: We analyzed microarray CEL file data downloaded from public databases of 28 global cohorts. A total of 2,454 patients with ER-positive breast cancer were analyzed for 42GC, and 1,263 of these, with complete clinicopathological data were analyzed for CTS5. RESULTS: In the analysis of recurrent patients, the 42GC LR and CTS5 low-risk group tended to have LR. Notably, in the analysis of patients with and without recurrence, the highest LR rate beyond 5 years was observed in the CTS5 high-risk group. The combination of the 42GC and CTS5 high-risk groups showed the highest LR rate (16.9%), significantly exceeding that of the 42GC non-LR (NLR) and CTS5 low-risk combination (5.41%) (p = 0.038, odds ratio = 3.53). Furthermore, incorporating a third factor, 95GC, potentially reduced the number of patients prioritized for extended hormonal therapy for approximately one-quarter of patients. CONCLUSIONS: Results confirmed that the two factors, gene expression profiles and clinicopathological factors, affect the time of recurrence. It also showed that the biological predisposition for LR (CTS5 low-risk) differed from the high LR rate (CTS5 high-risk). In clinical practice, patients with the 42GC LR and CTS5 high-risk combination should be prioritized for extended hormonal therapy. The addition of CTS5 and 95GC to 42GC allows for better risk classification of LR.

Additional statin treatment enhances the efficacy of HER2 blockade and improves prognosis in Rac1-high/HER2-positive breast cancer.

The prognosis of HER2-positive breast cancer (BC) has improved with the development of anti-HER2 therapies; however, the problem remains that there are still cases where anti-HER2 therapies do not respond well. We found that the expression of SREBF2, a master transcriptional factor in the mevalonate pathway, was correlated with ERBB2 (HER2) expression and a poor prognosis in HER2-positive BC. The target gene expressions of SREBF2 were associated with higher expression of ERBB2 in HER2-positive BC cells. Statins, anti-hypercholesterolemia drugs that inhibit the mevalonate pathway, enhanced the efficacy of HER2-targeting agents with inducing apoptosis in a geranylgeranylation-dependent manner. Mechanistically, statins specifically inhibited membrane localization of Rac1, a target protein of geranylgeranylation, and suppressed the activation of HER2 downstreams AKT and ERK pathways. Consistently, retrospective analysis showed a longer recurrence-free survival in Rac1-high/HER2-positive BC patients treated with HER2-targeting agents with statins than without statins. Our findings thus suggest that Rac1 expression could be used as a biomarker to stratify HER2-positive BC patients that could benefit from dual blockade, i.e., targeting HER2 with inhibition of geranylgeranylation of Rac1 using statins, thereby opening avenues for precision medicine in a new subset of Rac1-high/HER2-positive BC.

Eribulin versus S-1 as first or second-line chemotherapy to assess health-related quality of life and overall survival in HER2-negative metastatic breast cancer (RESQ study): a non-inferiority, randomised, controlled, open-label, phase 3 trial.

Background: Eribulin prolongs overall survival (OS) of patients with human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer (MBC), particularly in later chemotherapy (ChT) treatment. However, the health-related quality of life (HRQoL) and efficacy of first or second-line therapy in eribulin-treated patients remain unknown. Using eribulin in the first- or second-line may demonstrate the non-inferiority of HRQoL compared to S-1, an oral 5-fluorouracil derivative, while maintaining OS. Methods: This randomised, controlled, open-label, phase III trial was conducted at 50 hospitals in Japan. Patients were enrolled from June 2016 and October 2019. Patients with HER2-negative MBC once under or no previous ChT were randomly assigned (1:1) to receive eribulin or S-1. HRQoL was assessed using the European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire-Core 30 (QLQ-C30) every six weeks until week 24 and every nine weeks until week 42. The primary endpoint was the deterioration defined as more than 10 points worsening of the general health score of QLQ-C30 or death within one year after randomisation. The secondary endpoints included OS. (Trial ID: UMIN000021398). Findings: Three hundred and two patients were enrolled, with 152 and 148 assigned to the eribulin and S-1 groups, respectively. The questionnaire compliance rate was 85.6%. Risk difference of global health status deterioration through one year was -0.66% (95% CI: -12.47-11.16; non-inferiority P = 0.077) for eribulin compared to S-1 groups. Median time to first deterioration for global health status score was 5.64 (95% CI: 3.51-8.00) and 5.28 months (95% CI: 3.28-7.80) in the eribulin and S-1 groups, respectively. The median OS was 34.7 and 27.8 months, (HR: 0.72, 95% CI: 0.54-0.96; P = 0.026); the median progression-free survival was 7.57 and 6.75 months in the eribulin and S-1 groups, (HR: 0.88, 95% CI: 0.67-1.16; P = 0.35), respectively. No new adverse events occurred. Interpretation: The time of the first clinical deterioration was similar between the two groups and OS significantly increased in eribulin-treated patients. Funding: This study was funded by CSPOR-BC and Eisai CO., Ltd.