PIK3CA mutations are associated with pathologic complete response rate to neoadjuvant pyrotinib and trastuzumab plus chemotherapy for HER2-positive breast cancer

Mass Spectrometry-Based Proteomics for Next-Generation Precision Oncology

Cancer is the leading cause of death worldwide characterized by patient heterogeneity and complex tumor microenvironment. While the genomics-based testing has transformed modern medicine, the challenge of diverse clinical outcomes highlights unmet needs for precision oncology. As functional molecules regulating cellular processes, proteins hold great promise as biomarkers and drug targets. Mass spectrometry (MS)-based clinical proteomics has illuminated the molecular features of cancers and facilitated discovery of biomarkers or therapeutic targets, paving the way for innovative strategies that enhance the precision of personalized treatment. In this article, we introduced the tools and current achievements of MS-based proteomics, choice of discovery and targeted MS from discovery to validation phases, profiling sensitivity from bulk samples to single-cell level and tissue to liquid biopsy specimens, current regulatory landscape of MS-based protein laboratory-developed tests (LDTs). The challenges, success and future perspectives in translating research MS assay into clinical applications are also discussed. With well-designed validation studies to demonstrate clinical benefits and meet the regulatory requirements for both analytical and clinical performance, the future of MS-based assays is promising with numerous opportunities to improve cancer diagnosis, treatment, and monitoring.

Preclinical study and phase 2 trial of neoadjuvant pyrotinib combined with chemotherapy in luminal/HER2-low breast cancer: PILHLE-001 study

The prognosis of patients with luminal/human epidermal growth factor receptor 2 (HER2)-low early breast cancer (EBC) needs to be improved. This preclinical study and phase 2 trial (ChiCTR2100047233) aims to explore the efficacy and safety of pyrotinib (a pan-HER tyrosine kinase inhibitor) plus chemotherapy in this population. Our preclinical experiments indicate a synergistic anti-tumor effect of pyrotinib plus chemotherapy in luminal/HER2-low (immunochemistry [IHC] 2+/fluorescent in situ hybridization [FISH]-negative) breast cancer models. Furthermore, 48 women with luminal/HER2-low (IHC 2+/FISH-negative) high-risk EBC are enrolled to receive neoadjuvant pyrotinib plus chemotherapy (epirubicin-cyclophosphamide followed by docetaxel). Ultimately, 26 (54.2%; 95% confidence interval [CI] 39.2%-68.6%) patients achieve the primary endpoint (residual cancer burden [RCB] 0/I). Treatment-related adverse events of grade ≥3 occur in 21 (43.8%) patients, with the most prevalent being diarrhea (10 [20.8%]). In conclusion, neoadjuvant pyrotinib plus chemotherapy has encouraging efficacy and manageable toxicity in women with luminal/HER2-low (IHC 2+/FISH-negative) high-risk EBC. This regimen warrants to be further validated.

Targeted Sequencing of HER2-Positive Breast Cancer Mutations Revealed a Potential Association between PIK3CA and Trastuzumab Resistance

BACKGROUND

Different molecular subtypes, including HER2-positive, have been identified in breast cancer. The overexpression of HER2 triggers downstream signaling pathways such as the PI3K/AKT/mTOR pathway. Until recently, trastuzumab has been used as a single HER2-targeted therapy in Egypt. However, resistance to trastuzumab has been reported. Previous studies have demonstrated the genetic variants that affect the trastuzumab response. However in Egypt, few studies investigated molecular biomarkers such as p53 that might affect the trastuzumab response. Therefore, we aimed to extend the genetics workup of Her2 + BC to include important oncogenes and other vital cancer pathways.

METHODS

Formalin-fixed paraffin-embedded samples were collected from 24 HER2+ BC Egyptian patients, twelve patients in complete remission for 2 years or more from the start of trastuzumab and twelve resistant patients who relapsed or developed metastasis within 2 years from the start of trastuzumab. Somatic mutations in hotspot regions of 17 genes were further investigated using next-generation sequencing.

RESULTS

Among the total number of identified variants (106 variants), PIK3CA showed the most frequent variants, with more variants occurring in the resistant group than in the responsive group (P= 0.004). The frequency of PIK3CA mutations was greater in resistant patients than in responsive patients (P= 0.036). Additionally, there was a significant correlation between PIK3CA mutations and pathological complete response (pCR) (P=0.036). Most of PIK3CA variants in resistant patients were detected in exon 9 and 20. The PIK3CA variants His1047Tyr, Glu545Lys, His701Pro, Lys111Glu, Val344Gly and Tyr1021Cys were found only in the resistant patients, suggesting that they are associated with trastuzumab resistance.

CONCLUSION

PIK3CA variants were more frequent in resistant HER2+ BC patients than in responsive patients, with a significant correlation between PIK3CA mutation and a lower pCR rate. PIK3CA variants within exon 9 and 20 (such as Glu545Lys and His1047Tyr respectively) were associated with trastuzumab resistance.

Pyrotinib and trastuzumab combination treatment synergistically overcomes HER2 dependency in HER2-positive breast cancer: insights from the PHILA trial

BACKGROUND

The PHILA study suggests that pyrotinib, trastuzumab, and docetaxel significantly improved progression-free survival (PFS) compared with placebo, trastuzumab, and docetaxel in patients with untreated HER2-positive metastatic breast cancer. In this study, we aimed to investigate the synergistic mechanisms of pyrotinib plus trastuzumab and provide further insights for the PHILA trial.

METHODS

The in vitro activity of combination treatments was assessed through cell biological and biochemical experiments. The in vivo efficacy was evaluated in cell-derived xenografts, a TUBO tumour model, and one clinical case. Next-generation sequencing was performed on circulating tumour DNA (ctDNA) from patients in the PHILA trial.

FINDINGS

The combination of pyrotinib and trastuzumab more effectively inhibited cell growth than pyrotinib or trastuzumab alone in models of HER2-dependent breast cancer. It potentiated membrane HER2 ubiquitination and downregulation, which resulted in a comprehensive blockade of the HER2 signalling pathway. The pyrotinib-altered membrane HER2 levels had no significant effect on trastuzumab-mediated antibody-dependent cell-mediated cytotoxicity (ADCC). We further validated the synergistic mechanisms in TUBO tumours and one clinical case, rather than models of HCC1954 cells harbouring the PIK3CA H1047R mutation. Similarly, in our centre cohort of the PHILA study, patients with genetic alterations in the HER2 signalling cascade had significantly shorter median PFS than individuals with the wild-type pathway.

INTERPRETATION

Our findings underscore the robust synergy between pyrotinib and trastuzumab in overcoming HER2 dependency and provide a rationale for pyrotinib, trastuzumab, and docetaxel as one of the optimal choices for patients with untreated HER2-positive metastatic breast cancer, who are dependent on the HER2 signalling cascade.

FUNDING

This work was supported by the National Key Research and Development Program of China (2021YFF1201300), the National Natural Science Foundation of China (82172875), the CAMS Innovation Fund for Medical Sciences (CIFMS) (2022-I2M-2-001), and the Joint Innovative Fund of Beijing Natural Science Foundation and Changping District (L234004).

Prevalence and effect of PIK3CA H1047R somatic mutation among Indian head and neck cancer patients

PIK3CA is one among the several mutated genes in cancer, including head and neck squamous cell carcinoma (HNSCC). H1047R is a hotspot somatic mutation in PIK3CA that occurs most frequently in several forms of cancers. Distribution of PIK3CA H1047R mutation in Indian HNSCC patients was screened and its effect on disease progression and response to treatment was analysed in this study. Genomic DNA was extracted from tumour biopsies of HNSCC patients (n = 48) and polymerase chain reaction coupled restriction fragment length polymorphism (PCR-RFLP) technique was used to screen for the mutation. Overall survival (OS) and Progression-free survival (PFS) of the patients were calculated in order to study effect of this mutation on survival and response to treatment respectively. Results showed that irrespective of patients' criteria, twenty-five patients (52 %) carried a heterozygous form of mutation (His/Arg) and the rest (48 %) were wild type (His/His). The mean OS of the cohort with the mutation was 20.451 months (SE ± 1.710 months) while 26.31 months (SE ± 2.431) was in wild type population. PFS of the patients with the mutation was 18.612 months (SE ± 2.072), and for the wild type population, it was 26.31 months (SE ± 2.431). These observations suggest that Indian HNSCC patients with PIK3CA H1047R mutation have poor prognosis.

Safety and efficacy of pyrotinib for HER‑2‑positive breast cancer in the neoadjuvant setting: A systematic review and meta‑analysis

As a novel tyrosine kinase inhibitor (TKI), pyrotinib can irreversibly block dual pan-ErbB receptors and has been used in the treatment of advanced or metastatic human epidermal growth factor receptor 2 (HER2)-positive breast cancer. However, there are limited data on the use of pyrotinib in early breast cancer. Therefore, the present meta-analysis was conducted to evaluate the safety and efficacy of pyrotinib in the neoadjuvant setting for patients with early-stage or locally advanced HER2-positive breast cancer. Online databases (Pubmed, Web of Science, Embase and Cochrane Library) were comprehensively searched for eligible prospective clinical trials on August 17, 2023. The primary endpoint was the treatment-related adverse events (TRAEs), and the secondary endpoint was pathological complete response (pCR) rate. In total, seven trials with a total enrolment of 407 patients were included. A total of seven studies evaluated pyrotinib in combination with trastuzumab and chemotherapy in the neoadjuvant setting. The median age ranged from 47-50 years. The most common TRAEs were diarrhea [98% of patients; 95% confidence interval (CI): 92-100%], followed by anemia (71%; 95% CI: 55-89%), vomiting (69%; 95% CI: 55-82%), and leucopenia (66%; 95% CI: 35-91%). No treatment-related deaths occurred. The pooled pCR rate was 57% (95% CI: 47-68%). It was concluded that pyrotinib-containing neoadjuvant therapy could be an effective treatment strategy in patients with early-stage or locally advanced HER2-positive breast cancer; however, the management of adverse events should be a key consideration. The management of adverse events should be paid great attention to, during pyrotinib therapy, although pyrotinib-contained neoadjuvant therapy could be an effective treatment for patients with early-stage or locally advanced HER2-positive breast cancer. Head-to-head randomized clinical trials are warranted to further confirm the benefits and risks associated with pyrotinib therapy in patients with breast cancer.

Genomic and transcriptomic analysis of breast cancer identifies novel signatures associated with response to neoadjuvant chemotherapy

BACKGROUND

Neoadjuvant chemotherapy (NAC) has become a standard treatment strategy for breast cancer (BC). However, owing to the high heterogeneity of these tumors, it is unclear which patient population most likely benefit from NAC. Multi-omics offer an improved approach to uncovering genomic and transcriptomic changes before and after NAC in BC and to identifying molecular features associated with NAC sensitivity.

METHODS

We performed whole-exome and RNA sequencing on 233 samples (including matched pre- and post-treatment tumors) from 50 BC patients with rigorously defined responses to NAC and analyzed changes in the multi-omics landscape. Molecular features associated with NAC response were identified and validated in a larger internal, and two external validation cohorts, as well as in vitro experiments.

RESULTS

The most frequently altered genes were TP53, TTN, and MUC16 in both pre- and post-treatment tumors. In comparison with pre-treatment tumors, there was a significant decrease in C > A transversion mutations in post-treatment tumors (P = 0.020). NAC significantly decreased the mutation rate (P = 0.006) of the DNA repair pathway and gene expression levels (FDR = 0.007) in this pathway. NAC also significantly changed the expression level of immune checkpoint genes and the abundance of tumor-infiltrating immune and stroma cells, including B cells, activated dendritic cells, γδT cells, M2 macrophages and endothelial cells. Furthermore, there was a higher rate of C > T substitutions in NAC nonresponsive tumors than responsive ones, especially when the substitution site was flanked by C and G. Importantly, there was a unique amplified region at 8p11.23 (containing ADGRA2 and ADRB3) and a deleted region at 3p13 (harboring FOXP1) in NAC nonresponsive and responsive tumors, respectively. Particularly, the CDKAL1 missense variant P409L (p.Pro409Leu, c.1226C > T) decreased BC cell sensitivity to docetaxel, and ADGRA2 or ADRB3 gene amplifications were associated with worse NAC response and poor prognosis in BC patients.

CONCLUSIONS

Our study has revealed genomic and transcriptomic landscape changes following NAC in BC, and identified novel biomarkers (CDKAL1P409L, ADGRA2 and ADRB3) underlying chemotherapy resistance and poor prognosis, which could guide the development of personalized treatments for BC.

Somatic mutations in a multigene panel and impact on prognosis based on TP53 status in Chinese HER2-positive patients undergoing neoadjuvant therapy: A single-institution retrospective cohort

BACKGROUND

Gene mutations play a crucial role in the occurrence and development of tumors, particularly in breast cancer (BC). Neoadjuvant therapy (NAT) has shown greater clinical benefit in HER2-positive breast cancer. However, further clinical investigation is needed to fully understand the correlation between genetic mutations and NAT efficacy and the long-term prognosis in HER2-positive BC.

METHODS

This was a retrospective cohort study of 222 patients receiving NAT between 2017 and 2021 in the Department of Breast Surgery of Fudan University Shanghai Cancer Center. Tumor samples from these patients were subjected to Next Generation Sequencing (NGS) to analyze mutations in 513 cancer-related genes. This study aimed to investigate the association between these genetic mutations and postoperative pathological complete response (pCR), as well as their impact on disease-free survival (DFS).

RESULTS

In total, 48.65% patients reached pCR, ER-negative status (p < 0.001), PR-negative status (p < 0.001), Ki67 ≥ 20 (p = 0.011), and dual-targeted therapy (p < 0.001) were all associated with enhanced pCR rates. The frequency of somatic alterations in TP53 (60%), PIK3CA (15%), and ERBB2 (11%) was highest. In the HER2+/HR- cohort, patients who achieved pCR had a significant benefit in prognosis (HR = 3.049, p = 0.0498). KMT2C (p = 0.036) and TP53 (p = 0.037) mutations were significantly increased in patients with DFS events. Moreover, TP53 mutations had prognostic significance in HER2-positive BC patients with HR-negative (HR = 3.712, p = 0.027) and pCR (HR = 6.253, p = 0.027) status and who received herceptin-only targeted therapy (HR = 4.145, p = 0.011).

CONCLUSIONS

The genetic mutation profiles of Chinese HER2+ patients who received NAT were discrepant with respect to HR status or DFS events. TP53 mutations have significant prognostic value in patients with NAT for HER2-positive BC and patients benefit differently depending on HR status, the neoadjuvant regimen and response, which highlights the significance of genetic factors in treatment customization based on individual genetic and clinical characteristics.

Pyrotinib plus docetaxel as first-line treatment for HER2-positive metastatic breast cancer: the PANDORA phase II trial

The role of pyrotinib in the treatment of HER2-positive metastatic breast cancer (MBC) has been well-established. This multicenter, single-arm phase II trial (NCT03876587) aimed to assess the benefit of pyrotinib plus docetaxel as a first-line treatment for HER2-positive MBC. Women with HER2-positive MBC who had not undergone HER2 blockade or chemotherapy for metastatic disease were enrolled in the study and received daily oral pyrotinib 400 mg plus intravenous docetaxel 75 mg/m2 every 3 weeks. The primary endpoint was the objective response rate (ORR), secondary endpoints included progression-free survival (PFS), duration of response (DoR), clinical benefit rate (CBR), overall survival (OS) and safety. From June 2019 to June 2021, 79 patients were enrolled. The confirmed ORR was 79.7% (95% confidence interval [CI], 70.8-88.6), and the CBR was 87.3% (95%CI, 80.0-94.6) in the intention-to-treat population. The pre-specified primary endpoint was met. The median DoR was 15.9 months (interquartile range, 8.3-19.5); the median PFS was 16.0 months (95% CI, 11.2-20.8), and the median OS was not reached. The most common grade ≥3 treatment-related adverse events observed were leukopenia (29.1%), neutropenia (27.8%), and diarrhea (21.5%). This study demonstrates that pyrotinib plus docetaxel show an acceptable safety profile and promising antitumor activity as a first-line treatment option for patients with HER2-positive MBC.

A multicenter single-arm trial of neoadjuvant pyrotinib and trastuzumab plus chemotherapy for HER2-positive breast cancer

The objective of this multicenter, single-arm trial (ChiCTR1900022293) was to explore the efficacy and safety of neoadjuvant therapy with epirubicin, cyclophosphamide, and pyrotinib followed by docetaxel, trastuzumab, and pyrotinib (ECPy-THPy) in the treatment of patients with stage II-III HER2-positive breast cancer. The present study enrolled patients with stage II-III HER2-positive breast cancer. Epirubicin and cyclophosphamide were administrated for four 21-day cycles, followed by four cycles of docetaxel and trastuzumab. Pyrotinib was taken orally once per day throughout the treatment period. The primary endpoint was total pathological complete response (tpCR, ypT0/is ypN0) rate in the modified intention-to-treat (mITT) population. In total, 175 patients were included. The tpCR rate was 68.6% (95% CI, 60.7-75.8%), while the objective response rate was 89.1%. In the post-hoc subgroup analysis, no association between clinical characteristics and the tpCR rate was observed. The most common grade ≥3 adverse events were diarrhea (54.3%), followed by white blood cell count decreased (5.1%), and neutrophil count decreased (4.6%). In conclusion, the neoadjuvant regimen with ECPy-THPy showed promising pathological response and clinical benefits with an acceptable safety profile in patients with stage II-III HER2-positive breast cancer.

Association of PIK3CA mutation with outcomes in HER2-positive breast cancer treated with anti-HER2 therapy: A meta-analysis and bioinformatic analysis of TCGA‑BRCA data

BACKGROUND

This study aimed to comprehensively explore the clinical significance of PIK3CA mutation in human epidermal growth factor receptor 2 (HER2)-positive breast cancer treated with anti-HER2 therapy.

METHODS

We systematically searched PubMed, Embase, and the Cochrane databases for eligible studies assessing the association between PIK3CA mutation and outcomes in patients with HER2-positive breast cancer receiving anti-HER2 therapy. The main outcomes included: (1) pathological complete response (pCR) or disease-free survival (DFS) for the neoadjuvant setting; (2) DFS or invasive DFS for the adjuvant setting; (3) objective response rate (ORR), progression-free survival (PFS), time-to-progression (TTP), or overall survival (OS) for the metastatic setting. The mutational landscape of HER2-positive breast cancer according to PIK3CA mutation status was examined based on TCGA breast cancer dataset.

RESULTS

Totally, 43 eligible studies, covering 11,099 patients with available data on PIK3CA mutation status, were identified. In the neoadjuvant setting, PIK3CA mutation was significantly associated with a lower pCR rate (OR=0.23, 95% CI 0.19-0.27, p<0.001). This association remained significant irrespective of the type of anti-HER2 therapy (single-agent or dual-agent) and hormone receptor status. There were no significant differences in DFS between PIK3CA mutated and wild-type patients in either the neoadjuvant or adjuvant settings. In the metastatic setting, PIK3CA mutation predicted worse ORR (OR=0.26, 95%CI 0.17-0.40, p<0.001), PFS (HR=1.28, 95%CI 1.03-1.59, p = 0.024) and TTP (HR=2.27, 95%CI 1.54-3.34, p<0.001). However, no significant association was observed between PIK3CA mutation status and OS. Distinct mutational landscapes were observed in HER2-positive breast cancer between individuals with PIK3CA mutations and those with wild-type PIK3CA.

CONCLUSIONS

PIK3CA mutation was significantly associated with a lower pCR rate in HER2-positive breast cancer treated with neoadjuvant anti-HER2 therapy. In the metastatic setting, PIK3CA mutation was predictive of worse ORR, PFS and TTP. These results suggest the potential for developing PI3K inhibitors as a therapeutic option for these patients.

Pyrotinib-based therapeutic approaches for HER2-positive breast cancer: the time is now

Human epidermal growth factor receptor 2 (HER2)-positive breast cancer (BC) is a highly aggressive subtype associated with poor prognosis. The advent of HER2-targeted drugs, including monoclonal antibodies, tyrosine-kinase inhibitors (TKIs) and antibody-drug conjugates, has yielded improved prognosis for patients. Compared with widely used monoclonal antibodies, small-molecule TKIs have unique advantages including oral administration and favorable penetration of blood-brain barrier for brain metastatic BC, and reduced cardiotoxicity. Pyrotinib is an irreversible TKI of the pan-ErbB receptor, and has recently been shown to be clinically effective for the treatment of HER2-positive BC in metastatic and neoadjuvant settings. This review highlights the development on the application of pyrotinib-based therapeutic approaches in the clinical settings of HER2-positive BC.

Dysregulated Signalling Pathways Driving Anticancer Drug Resistance

One of the leading causes of death worldwide, in both men and women, is cancer. Despite the significant development in therapeutic strategies, the inevitable emergence of drug resistance limits the success and impedes the curative outcome. Intrinsic and acquired resistance are common mechanisms responsible for cancer relapse. Several factors crucially regulate tumourigenesis and resistance, including physical barriers, tumour microenvironment (TME), heterogeneity, genetic and epigenetic alterations, the immune system, tumour burden, growth kinetics and undruggable targets. Moreover, transforming growth factor-beta (TGF-β), Notch, epidermal growth factor receptor (EGFR), integrin-extracellular matrix (ECM), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), phosphoinositol-3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR), wingless-related integration site (Wnt/β-catenin), Janus kinase/signal transducers and activators of transcription (JAK/STAT) and RAS/RAF/mitogen-activated protein kinase (MAPK) signalling pathways are some of the key players that have a pivotal role in drug resistance mechanisms. To guide future cancer treatments and improve results, a deeper comprehension of drug resistance pathways is necessary. This review covers both intrinsic and acquired resistance and gives a comprehensive overview of recent research on mechanisms that enable cancer cells to bypass barriers put up by treatments, and, like "satellite navigation", find alternative routes by which to carry on their "journey" to cancer progression.