Baseline Mutations and Up-Regulation of PI3K-AKT Pathway Serve as Potential Indicators of Lack of Response to Neoadjuvant Chemotherapy in Stage II/III Breast Cancer

HER2-low status may predict poor neoadjuvant chemotherapy response in HR-negative breast cancer: a real-world multicenter study

OBJECTIVE

We aimed to investigate the impact of human epidermal growth factor receptor 2 status (human epidermal growth factor receptor 2-low versus human epidermal growth factor receptor 2-zero) on pathological response to neoadjuvant chemotherapy and survival outcomes in early-stage breast cancer.

METHODS

Patients with primary invasive breast cancer received neoadjuvant chemotherapy between July 2018 and July 2021 were identified from six hospitals. The primary efficacy end-point was total pathological complete response. The second short-term efficacy end-points include breast pathological complete response, axillary lymph nodes pathological complete response and the score of Miller-Payne grade. Long-term efficacy end-point was disease-free survival.

RESULTS

429 patients with human epidermal growth factor receptor 2 negative invasive tumors were included, 267 (62.24%) had human epidermal growth factor receptor 2-low tumors. Hormone receptor-positive patients had a higher percentage of human epidermal growth factor receptor 2-low tumors compared to hormone receptor-negative patients (71.97% versus 42.14%). The pathological response rate was significantly lower in human epidermal growth factor receptor 2-low tumors than in human epidermal growth factor receptor 2-zero tumors for total patients in univariate analysis, including the rates of total pathological complete response (5.2% versus 14.2%), breast pathological complete response (6.4% versus 17.3%), nodes pathological complete response (26.3% versus 37.7%) and MP4-5 (21.2% versus 33.8%). Subgroup analysis showed that the rates of total pathological complete response, breast pathological complete response and MP4-5 were also significantly lower in human epidermal growth factor receptor 2-low tumors versus human epidermal growth factor receptor 2-zero tumors in both univariate and multivariate analysis in hormone receptor-negative subgroup. With the median follow-up of 24 months, disease-free survival was comparable between these two subgroups (P = 0.816).

CONCLUSIONS

Our results demonstrate that human epidermal growth factor receptor 2-low tumors achieved a significantly lower pathological complete response rate with conventional chemotherapy than those with human epidermal growth factor receptor 2-zero tumors, especially for hormone receptor-negative group. Large, randomized, prospective studies are needed to confirm our data and further evaluate the prognostic value of human epidermal growth factor receptor 2-low expression.

Anti-tumor effects of low-dose metronomic vinorelbine in combination with alpelisib in breast cancer cells

In metastatic breast cancer (MBC), PIK3CA mutations, activating the phosphatidylinositol 3-kinase (PI3K) signaling pathway seem to be associated with chemotherapy resistance and poor outcome. Inhibition of the PI3K signaling pathway may lead to sensitization and prevention of the development of resistance to cytotoxic drugs. The present study aimed to investigate the anti-tumor activity of low-dose vinorelbine (VRL) combined with alpelisib, an α-selective PI3K inhibitor and degrader, in breast cancer (BC) cells. Human BC cell lines MCF-7, T-47D [both hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative, PIK3CA-mutated], MDA-MB-231 and BT-549 (both triple-negative, wild-type PIK3CA) were exposed to a combination of low-dose VRL and alpelisib for 3 and 7 days. Cell viability was detected by the Alamar blue assay, and cell proliferation was determined by the BrdU incorporation. The effect of the substances on the p110α protein expression that is encoded by PIK3CA gene was investigated by Western blot. Low-dose VRL plus alpelisib showed synergistic anti-tumor effects and significantly inhibited cell viability and proliferation of MCF-7 and T-47D cells. Even lower alpelisib concentrations (10 ng/ml and 100 ng/ml) combined with low-dose metronomic VRL led to a significant reduction of cell viability of PIK3CA-mutated cells, and the anti-tumor activity was comparable with the effects at 1000 ng/ml alpelisib. Cell viability and proliferation of MDA-MB-231 and BT-549 cells were inhibited by VRL but not by alpelisib alone. This indicates that alpelisib did not significantly affect the cell growth of triple-negative, PIK3CA wild-type BC cells. The p110α expression was downregulated or not affected in PIK3CA-mutated cell lines, and not significantly upregulated in PIK3CA wild-type cell lines. In conclusion, combination of low-dose metronomic VRL and alpelisib showed synergistic anti-tumor effects and significantly inhibited the growth of HR-positive, HER2-negative, PIK3CA-mutated BC cells, providing a rationale for further efforts to evaluate this combination in vivo.

Anthracycline-Free Neoadjuvant Treatment in Patients with HER2-Positive Breast Cancer: Real-Life Use of Pertuzumab, Trastuzumab and Taxanes Association with an Exploratory Analysis of PIK3CA Mutational Status

Simple Summary

This retrospective observational study aims at highlighting the response to pertuzumab, trastuzumab and docetaxel treatment (THP), without using anthracycline, in patients with HER2-positive early breast cancer. We add evidence to the suitability of THP in real life to reach higher pathological complete response rates, with a good safety profile for patients. An exploratory analysis of the mutational status of PIK3CA was performed as well, and 21% mutated samples were identified, with overall higher pCR rates in PIK3CA mutant patients and, particularly, in those who were THP-treated. Our original results open the door to further studies focused on more in-depth analysis of the molecular and clinical features related to the response to anthracycline-free neoadjuvant treatment in HER2-positive early breast cancer patients.

Abstract

HER2 is considered one of the most traditional prognostic and predictive biomarkers in breast cancer. Literature data confirmed that the addition of pertuzumab to a standard neoadjuvant chemotherapy backbone (either with or without anthracyclines), in patients with human epidermal growth factor receptor 2 (HER2)-positive early breast cancer (EBC), leads to a higher pathological complete response (pCR) rate, which is known to correlate with a better prognosis. In this retrospective analysis, 47 consecutive patients with HER2-positive EBC received sequential anthracyclines and taxanes plus trastuzumab (ATH) or pertuzumab, trastuzumab and docetaxel (THP). Despite the limited sample size, this monocentric experience highlights the efficacy (in terms of pCR) and safety of THP in the neoadjuvant setting of HER2-positive EBC as an anthracycline-free approach. Given the role of PIK3CA as a prognostic and therapeutic target in breast cancer, tumors were also analyzed to assess the PIK3CA mutational status. Thirty-eight out of forty-seven patients were evaluated, and PIK3CA variants were identified in 21% of tumor samples: overall, one mutation was detected in exon 4 (2.6%), two in exon 9 (5.3%) and four in exon 20 (10.5%). Of note, one sample showed concurrent mutations in exons 9 (codon 545) and 20 (codon 1047). Among patients reaching pCR (n = 13), 38.5% were PIK3CA mutants; on the other hand, among those lacking pCR (n = 25), just 12% showed PIK3CA variants. Regarding THP-treated mutant patients (n = 5), 80% reached pCR (three hormone-receptor-negative, one hormone-receptor-positive). Interestingly, the only patient not achieving pCR had a tumor with two co-occurring PIK3CA mutations. In conclusion, this study provides new evidence about the efficacy and good safety profile of THP, compared to the ATH regimen, as an anthracycline-free neoadjuvant treatment of HER2-positive EBC. Further studies on larger/multicentric cohorts are planned for more in-depth analysis to confirm our molecular and clinical results.

Adult diffuse midline gliomas H3 K27-altered: review of a redefined entity

INTRODUCTION

Diffuse midline glioma (DMG) H3 K27-altered is a type of high-grade gliomas first recognized as a new entity in the 2016 World Health Organization Classification of Central Nervous System (CNS) Tumors as DMG H3 K27M-mutant, recently renamed in the new 2021 WHO classification. The aim of this review is to describe the characteristics of diffuse midline gliomas H3 K27-altered in the adult population.

METHODS

We performed a review of the current literature regarding the genetic, clinical, imaging characteristics and management of diffuse midline gliomas H3 K27-altered in adult patients.

RESULTS

The 2021 WHO classification now designates the previously recognized DMG H3K27M-mutant as DMG H3 K27-altered, recognizing the alternative mechanisms by which the pathogenic pathway can be altered. Thus, the diagnostic criteria for this entity consist of diffuse growth pattern, midline anatomic location, and H3 K27-specific neuroglial mutations. DMGs' characteristic midline location makes them difficult to surgically resect and biopsy, carrying high mortality and morbidity rates, with median survival ranging from 9 to 12 months in adult patients.

CONCLUSION

The diagnosis of DMGs H3 K27-altered in adult patients should be considered upon neurological symptoms associated with an infiltrative midline brain tumor detected on imaging. Future studies are necessary to continue refining their characteristics in this age group.