Different prognostic roles of mutations in the helical and kinase domains of the PIK3CA gene in breast carcinomas

AutoEpiCollect, a Novel Machine Learning-Based GUI Software for Vaccine Design: Application to Pan-Cancer Vaccine Design Targeting PIK3CA Neoantigens

Previous epitope-based cancer vaccines have focused on analyzing a limited number of mutated epitopes and clinical variables preliminarily to experimental trials. As a result, relatively few positive clinical outcomes have been observed in epitope-based cancer vaccines. Further efforts are required to diversify the selection of mutated epitopes tailored to cancers with different genetic signatures. To address this, we developed the first version of AutoEpiCollect, a user-friendly GUI software, capable of generating safe and immunogenic epitopes from missense mutations in any oncogene of interest. This software incorporates a novel, machine learning-driven epitope ranking method, leveraging a probabilistic logistic regression model that is trained on experimental T-cell assay data. Users can freely download AutoEpiCollectGUI with its user guide for installing and running the software on GitHub. We used AutoEpiCollect to design a pan-cancer vaccine targeting missense mutations found in the proto-oncogene PIK3CA, which encodes the p110ɑ catalytic subunit of the PI3K kinase protein. We selected PIK3CA as our gene target due to its widespread prevalence as an oncokinase across various cancer types and its lack of presence as a gene target in clinical trials. After entering 49 distinct point mutations into AutoEpiCollect, we acquired 361 MHC Class I epitope/HLA pairs and 219 MHC Class II epitope/HLA pairs. From the 49 input point mutations, we identified MHC Class I epitopes targeting 34 of these mutations and MHC Class II epitopes targeting 11 mutations. Furthermore, to assess the potential impact of our pan-cancer vaccine, we employed PCOptim and PCOptim-CD to streamline our epitope list and attain optimized vaccine population coverage. We achieved a world population coverage of 98.09% for MHC Class I data and 81.81% for MHC Class II data. We used three of our predicted immunogenic epitopes to further construct 3D models of peptide-HLA and peptide-HLA-TCR complexes to analyze the epitope binding potential and TCR interactions. Future studies could aim to validate AutoEpiCollect's vaccine design in murine models affected by PIK3CA-mutated or other mutated tumor cells located in various tissue types. AutoEpiCollect streamlines the preclinical vaccine development process, saving time for thorough testing of vaccinations in experimental trials.

PIK3CA mutation-driven immune signature as a prognostic marker for evaluating the tumor immune microenvironment and therapeutic response in breast cancer

PURPOSE

Gene mutations drive tumor immune microenvironment (TIME) heterogeneity, in turn affecting prognosis and immunotherapy efficacy. PIK3CA is the most frequently mutated gene in breast cancer (BC), yet its relevance to BC prognosis remains controversial. Herein, we sought to determine the impact of PIK3CA mutation-driven immune genes (PDIGs) on BC prognosis in relation to TIME heterogeneity.

METHODS

PIK3CA mutation characteristics were compared and verified between the TCGA-BRCA dataset and a patient cohort from our hospital. PIK3CA mutation-driven differentially expressed genes were identified for consensus clustering and weighted gene co-expression network analysis to select the modules most relevant to the immune subtype. Thereafter, the two were intersected to obtain PDIGs. Univariate Cox, LASSO, and multivariate Cox regression analyses were sequentially performed on PDIGs to obtain a PIK3CA mutation-driven immune signature (PDIS), which was then validated using the Gene Expression Omnibus (GEO) database. Differences in functional enrichment, mutation landscape, immune infiltration, checkpoint gene expression, and drug response were compared between different risk groups.

RESULTS

PIK3CA mutation frequencies in the TCGA and validation cohorts were 34.49% and 40.83%, respectively. PIK3CA mutants were significantly associated with ER, PR, and molecular BC subtypes in our hospital cohort. The PDIS allowed for effective risk stratification and exhibited prognostic power in TCGA and GEO sets. The low-risk patients exhibited greater immune infiltration, higher expression of common immune checkpoint factors, and lower scores for tumor immune dysfunction and exclusion.

CONCLUSION

The PDIS can be used as an effective prognostic model for predicting immunotherapy response to guide clinical decision-making.

Somatic Mutations in Latin American Breast Cancer Patients: A Systematic Review and Meta-Analysis

(1) Background: Somatic mutations may be connected to the exposome, potentially playing a role in breast cancer's development and clinical outcomes. There needs to be information regarding Latin American women specifically, as they are underrepresented in clinical trials and have limited access to somatic analysis in their countries. This study aims to systematically investigate somatic mutations in breast cancer patients from Latin America to gain a better understanding of tumor biology in the region. (2) Methods: We realize a systematic review of studies on breast cancer in 21 Latin American countries using various databases such as PubMed, Google Scholar, Web of Science, RedAlyc, Dianlet, and Biblioteca Virtual en Salud. Of 392 articles that fit the criteria, 10 studies have clinical data which can be used to create a database containing clinical and genetic information. We compared mutation frequencies across different breast cancer subtypes using statistical analyses and meta-analyses of proportions. Furthermore, we identified overexpressed biological processes and canonical pathways through functional enrichment analysis. (3) Results: 342 mutations were found in six Latin American countries, with the TP53 and PIK3CA genes being the most studied mutations. The most common PIK3CA mutation was H1047R. Functional analysis provided insights into tumor biology and potential therapies. (4) Conclusion: evaluating specific somatic mutations in the Latin American population is crucial for understanding tumor biology and determining appropriate treatment options. Combining targeted therapies may improve clinical outcomes in breast cancer. Moreover, implementing healthy lifestyle strategies in Latin America could enhance therapy effectiveness and clinical outcomes.

InDEP: an interpretable machine learning approach to predict cancer driver genes from multi-omics data

Cancer driver genes are critical in driving tumor cell growth, and precisely identifying these genes is crucial in advancing our understanding of cancer pathogenesis and developing targeted cancer drugs. Despite the current methods for discovering cancer driver genes that mainly rely on integrating multi-omics data, many existing models are overly complex, and it is difficult to interpret the results accurately. This study aims to address this issue by introducing InDEP, an interpretable machine learning framework based on cascade forests. InDEP is designed with easy-to-interpret features, cascade forests based on decision trees and a KernelSHAP module that enables fine-grained post-hoc interpretation. Integrating multi-omics data, InDEP can identify essential features of classified driver genes at both the gene and cancer-type levels. The framework accurately identifies driver genes, discovers new patterns that make genes as driver genes and refines the cancer driver gene catalog. In comparison with state-of-the-art methods, InDEP proved to be more accurate on the test set and identified reliable candidate driver genes. Mutational features were the primary drivers for InDEP's identifying driver genes, with other omics features also contributing. At the gene level, the framework concluded that substitution-type mutations were the main reason most genes were identified as driver genes. InDEP's ability to identify reliable candidate driver genes opens up new avenues for precision oncology and discovering new biomedical knowledge. This framework can help advance cancer research by providing an interpretable method for identifying cancer driver genes and their contribution to cancer pathogenesis, facilitating the development of targeted cancer drugs.

Genetic analysis of oligo-recurrence breast cancer: correlation with clinical outcomes

BACKGROUND

We aimed to identify the relationship between the genomic characteristics and clinical outcomes of oligo-metastatic breast cancer.

METHODS

Oligo-metastatic breast cancer diagnosed by pathology from January 2001 and August 2019 were reviewed and we matched the poly-metastatic patients based on the clinicopathological features of patients included. Clinicopathological values and data of genomic alterations were collected. Oligo-recurrence (oligo-R) was defined as a situation where disease progression occurred in less than 5 anatomical sites and other anatomic areas still suppressed by the ongoing therapy.

RESULTS

A total of 26 breast cancer patients were enrolled in our study, including 14 patients with strict oligo-metastatic disease (oligo-R > 6 months) and 12 with simultaneous poly-metastatic disease. PIK3CA, TP53 and ERBB2 were the most common shared alterations identified in patients included. Based on the median time of oligo-R, we divided the patients with oligo-metastasis into longer oligo-R group (oligo-R > 31.04 months) and shorter oligo-R group (oligo-R ≤ 31.04 months). The analysis of PIK3CA mutation sites showed that H1047R mutation was closely associated with oligo-metastasis, rather than poly-metastasis. H1047R mutation also predicted a better prognosis (oligo-R > 31.04 months) in oligo-metastatic breast cancer. In addition, HER2 positive was more likely to be related to a good outcome in patients with oligo-metastasis.

CONCLUSIONS

Through the genetic analysis of samples from oligo-metastasis, we found the prognostic values of PIK3CA H1047R and HER2 in oligo- and poly-metastasis. We improved the stratification of prognosis and provided new insights for biological behaviors of oligo-metastatic breast cancer.

Frequency and Mutational Spectrum of PIK3CA gene mutations in Breast Cancer Patients: Largest and First Report from Lebanon

The PIK3CA pathway is one of the most frequently altered pathways in human cancers, especially in breast cancer with approximately 40% of HR+/HER2- advanced breast cancer cases exhibiting mutations in the PIK3CA gene. While the mutations can occur across the entire gene, the most common are observed in exon 9 corresponding to the helical domain, and in exon 20 encompassing the kinase domain. This study constitutes the first attempt at determining the frequency and mutational spectrum in Lebanese breast cancer patients. For this purpose, DNA samples from 280 breast cancer patients from across Lebanon were screened for PIK3CA mutations using the Therascreen® PIK3CA RGQ Real-time PCR assay. In line with previous reports, 38.57% of cases were positive for at least one PIK3CA mutation, among which approximately 59% were in exon 9 and 37% in exon 20. However, PIK3CA mutations are breast cancer are heterogeneous whereby 20% of known PIK3CA mutants might not be detected by compact PCR based assays. Thus, the adoption of comprehensive Next Generation Sequencing based panels to decipher the complete clinical, molecular and immunohistochemical profile of breast cancer tumor requires further investigation.

Phosphoinositide 3-Kinase (PI3K) Inhibitors and Breast Cancer: An Overview of Current Achievements

The phosphatidylinositol 3-kinase (PI3K) pathway is one of the most altered pathways in human cancers, and it plays a central role in cellular growth, survival, metabolism, and cellular mobility, making it a particularly interesting therapeutic target. Recently, pan-inhibitors and then selective p110α subunit inhibitors of PI3K were developed. Breast cancer is the most frequent cancer in women and, despite therapeutic progress in recent years, advanced breast cancers remain incurable and early breast cancers are at risk of relapse. Breast cancer is divided in three molecular subtypes, each with its own molecular biology. However, PI3K mutations are found in all breast cancer subtypes in three main "hotspots". In this review, we report the results of the most recent and main ongoing studies evaluating pan-PI3K inhibitors and selective PI3K inhibitors in each breast cancer subtype. In addition, we discuss the future of their development, the various potential mechanisms of resistance to these inhibitors and the ways to circumvent them.

Enzyme-Free Colorimetric Method for Fast Detection of PIK3CA Gene Mutation by Praseodymia Nanorods

The frequently mutated phosphatidylinositol 3-kinase catalytic subunit alpha (PIK3CA) gene is associated with multiple tumors and endocytosis of viruses. Identification of muted nucleotides at the hotspot can help in finding the susceptible people who are vulnerable to cancers and viruses. Herein, a simple enzyme-free colorimetric method is developed for the quick detection of PIK3CA gene mutations. The main mechanism lies in the dissimilar interactions between praseodymia nanorods and different nucleotides, as well as the underlying oxidase-mimicking characteristics of praseodymia. With rational designs of probes and processes, this method has great potential for expanded applications in the screening of mutations in other genes of interest.

Clinicopathological characteristics and prognostic analysis of PIK3CA mutation in breast cancer patients in Northwest China

PURPOSE

Multiple studies on PIK3CA mutations in breast cancer (BC) had been performed, which showed the controversial results among different countries and races even those from the same country. The present study aimed to explore the PIK3CA gene mutation status in BC patients in Northwest China and reveal the relationship between PIK3CA mutations and clinicopathological features along with prognosis.

MATERIALS AND METHODS

1002 BC patients from Northwest China were recruited in this study, genomic DNA was extracted from formalin-fixed paraffin-embedded (FFPE) tumor tissues, and hotspot mutations in the exon 9 and 20 of PIK3CA gene were detected by ARMS-PCR.

RESULTS

PIK3CA mutations were found in 31.2% (313/1002) of BC patients, among them 66.1% were mutations in exon 20% and 32.6% were mutations in exon 9. H1047R was the most common mutation type, accounting for 56.5% of the total mutated samples. Significant correlations were observed between PIK3CA mutation status and age (P = 0.035), histopathologic types (P = 0.004), pathological grade (P = 0.013), ER positivity (P < 0.001), PR positivity (P < 0.001), molecular subtypes (P = 0.004) and family history (P = 0.007). Cox multivariate analysis showed that patients with mutations in exon 9 or 20 had shorter DFS and OS than wild-type patients. Those with exon 9 mutations subgroup had the worst prognosis. Interestingly, patients with H1047L mutation had the best prognosis than others.

CONCLUSION

PIK3CA mutations could be used as an indicator of clinical outcome or targeted therapy for multiple breast cancer subgroups in Northwest China.

Physiological expression of PI3K H1047R mutation reveals its anti-metastatic potential in ErbB2-driven breast cancer

p110α is a catalytic subunit of phosphoinositide 3-kinase (PI3K), a major downstream effector of receptor tyrosine kinase ErbB2, that is amplified and overexpressed in 20-30% of breast cancers, 40% of which have an activating mutation in p110α. Despite the high frequency of PIK3CA gain-of-function mutations, their prognostic value is controversial. Here, we employ a knock-in transgenic strategy to restrict the expression of an activated form of ErbB2 and p110α kinase domain mutation (p110α^HR) in the mammary epithelium. Physiological levels of transgene expression under the control of their endogenous promoters did not result in a major synergistic effect. However, tumors arising in ErbB2/p110α^HR bi-genic strain metastasized to the lung with significantly reduced capacity compared to tumors expressing ErbB2 alone. The reduced metastasis was further associated with retention of the myoepithelial layer reminiscent of ductal carcinoma in situ (DCIS), a non-invasive stage of human breast cancer. Molecular and biochemical analyses revealed that these poorly metastatic tumors exhibited a significant decrease in phospho-myosin light chain 2 (MLC2) associated with cellular contractility and migration. Examination of human samples for MLC2 activity revealed a progressive increase in cellular contractility between non-invasive DCIS and invasive ductal carcinoma. Collectively, these data argue that p110α^HR mutation attenuates metastatic behavior in the context of ErbB2-driven breast cancer.

Design of a targeted next-generation DNA sequencing panel for pediatric T-cell lymphoblastic lymphoma to unravel biology and optimize treatment

Low incidence and molecular heterogeneity of pediatric T-cell lymphoblastic lymphoma (T-LBL) require an international, large-scale effort to identify novel clinical biomarkers. The ongoing international clinical trial LBL2018 (NCT04043494) represents an ideal opportunity to implement a common analytic approach. Targeted next-generation sequencing is well-suited for this purpose; however, selection of relevant target genes for T-LBL remains subject of ongoing debates. Our group has recently designed and evaluated a first target panel of 80 candidate genes for T-LBL. The present study aimed at developing a novel optimized gene panel for large-scale application and to promote an international agreement on a common core panel. Small sequence variants obtained from our former study were systematically analyzed and classified with regards to pathogenic relevance, to prioritize candidate genes. Additional genes were curated from literature and online databases for a more comprehensive analysis of relevant functions and signaling pathways. The new target panel TGP-T-LBL entails 84 candidate genes which are key actors in NOTCH, PI3K-AKT, JAK-STAT, RAS signaling, epigenetic regulation, transcription, DNA repair, cell cycle regulation and ribosomal function. From our former gene panel, 35 out of 80 candidate genes were selected for the novel panel. Forty-six out of 84 genes are currently being analyzed in the ongoing international trial LBL2018. Exploratory analysis of prognostic relevance on mutation-level suggested a potential association of PIK3CA variants c.1624G > A(p.Glu542Lys) and c.1633G > A(p.Glu545Lys) to occurrence of relapse, emphasizing particular relevance of mutation analysis in PI3K-AKT signaling. Our approach promotes comprehensive and clinically relevant mutational profiling of pediatric T-LBL. This article is protected by copyright. All rights reserved.

PIK3CA co-occurring mutations and copy-number gain in hormone receptor positive and HER2 negative breast cancer

We aim to elucidate the prognostic value of PIK3CA mutations and copy number (CN) gain (PIK3CA-mut/gain) in hormone receptor-positive and HER2-negative (HR + /HER2−) breast cancer (BC). We analyzed primary HR + /HER2− BC from three publicly available datasets comprising over 2000 samples and assessed the associations with tumoral and clinical characteristics and outcome. Clinical benefit (CB) in alpelisib-treated patients from two studies including 46 patients was analyzed. About 8–10% of HR + /HER2− primary BC had PIK3CA-mut/gain. In two of the datasets analyzed, among patients with PIK3CA mutant tumors, those with mut/gain had significantly worse outcome compared to those with CN neutral (PIK3CA-mut/neut) and PIK3CA-mut/gain remained an independent prognostic factor. CB of alpelisib-treated patients with PIK3CA-mut/gain and PIK3CA-mut/neut tumors was comparable. PIK3CA CN might help clarifying the prognostic and predictive role of PIK3CA mutations. Further studies are warranted.

Apolipoprotein B mRNA-Editing Catalytic Polypeptide-Like-Induced Protein Changes in Estrogen Receptor-Positive, Human Epidermal Growth Factor Receptor 2-Negative Breast Cancer Throughout Disease Progression

PURPOSE

Apolipoprotein B mRNA-Editing Catalytic Polypeptide-like (APOBEC) enzymes are mutagenic factors contributing to tumor progression and therapy resistance. However, the effects of APOBEC-induced protein changes have not been systematically assessed. Here, we describe the effects of APOBEC on the coding sequence in primary and metastatic estrogen receptor–positive (ER+)/human epidermal growth factor receptor 2–negative (HER2–) breast cancer (BC).

METHODS

We determined the enrichment of amino acid (AA) changes resulting from APOBEC mutagenesis in 323 primary BC tumors and 424 metastatic breast cancer (mBC) lesions via comparison with a simulated mutational genomic landscape not under selection pressure. We subsequently explored genes with recurrent APOBEC-associated AA changes and investigated the clonality of individual APOBEC-associated mutations. Using public sequencing data from an independent primary BC and mBC cohort, we further confirm our findings by reporting genes having these enriched AA changes in an APOBEC context.

RESULTS

Our analysis demonstrated that several APOBEC-derived AA changes are significantly enriched compared with a simulated AA change distribution drawn at random. Among the enriched AA changes, Glutamate(E)>Lysine(K) and Glutamate(E)>Glutamine(Q) were mostly found at hotspots in oncogenes, whereas termination codons (Glutamine[Q]>STOP[X] and Serine[S]>STOP[X]) occurred in tumor suppressor genes and, mostly, not at hotspot locations. These mutations are found in genes contributing to BC initiation, eg, introduction of termination codons in TP53, MAP3K1, and CDH1 (in lobular BC) and two oncogenic hotspots in PIK3CA (p.E542K and p.E545K). In endocrine-resistant BC, we observed APOBEC-induced termination codons at ER-modulating genes, KMT2C, ARID1A, NF1, and ZFHX3. Finally, in mBC, compared with single PIK3CA mutations, dual PIK3CA mutations occurred more frequently in an APOBEC context (Fisher's exact P < .001).

CONCLUSION

Our results show that APOBEC mutagenesis recurrently targets various known drivers of BC initiation, progression, and endocrine resistance.

APOBEC drives early, metastatic and endocrine resistant disease in ER+/HER2- breast cancer

Mutational pattern of PIK3CA exon 20 in circulating DNA in breast cancer

Breast cancer (BC) is one of the most common cancers with diverse mutations, etiology and causes. Mutational signature of the driver genes could allow for better understanding disease etiology and progression. This study aims to assess PIK3CA Exon 20 somatic mutational signature in relation to potential underlying etiology. Circulating DNA of 71 Egyptian BC patients was isolated, amplified for PIK3CA Exon 20, and sequenced. Mutational signature was determined according to COSMIC v2 signature. Public BC dataset was analysed to assess PIK3CA mutations effect on the transcriptomic profile. Somatic mutations of PIK3CA exon 20 were found in 66.2% of the study cohort. Nucleotide substitution patterns were similar to general nucleotide substitution patterns in BC. Signature 3 and 9 were the most common signatures in the studied BC patients. Signature of Aristolochic acid exposure was found in some cases. The most common nucleotide substitution was T > A transversion, but substitutions T > G and T > C were correlated to each other and to the total mutation number. PIK3CA mutations were found to disrupt several pathways including RAC1, PDGF, Wnt, and integrin signalling. PIK3CA exon 20 mutational signatures in Egyptian BC patients could suggest a disease etiology involving homologous recombination deficiency (HRD) and polymerase eta (Pol η). Nucleotide substitution patterns could indicate the role of exposure to oxidative stress and some carcinogens such as 4-aminobiphenyl and Aristolochic acid.

Identification of Pathway-Based Biomarkers with Crosstalk Analysis for Overall Survival Risk Prediction in Breast Cancer

Recently, many studies have investigated the role of gene-signature on the prognostic assessment of breast cancer (BC), however, the tumor heterogeneity and sequencing noise have limited the clinical usage of these models. Pathway-based approaches are more stable to the perturbation of certain gene expression. In this study, we constructed a prognostic classifier based on survival-related pathway crosstalk analysis. We estimated pathway’s deregulation scores (PDSs) for samples collected from public databases to select survival-related pathways. After pathway crosstalk analysis, we conducted K-means clustering analysis to cluster the patients into G1 and G2 subgroups. The survival outcome of the G2 subgroup was significantly worse than the G1 subgroup. Internal and external dataset exhibits high consistency with the training dataset. Significant differences were found between G2 and G1 subgroups on pathway activity, gene mutation, immune cell infiltration levels, and in particular immune cells/pathway’s activities were significantly negatively associated with BC patient’s outcomes. In conclusion, we established a novel classifier reflecting the overall survival risk of BC and successfully validated its clinical usage on multiple BC datasets, which could offer clinicians inspiration in formulating the clinical treatment plan.

Radioresistance and genomic alterations in head and neck squamous cell cancer: Sub-analysis of the ProfiLER protocol

BACKGROUND

Genome analysis could provide tools to assess predictive molecular biomarkers of radioresistance.

METHODS

Head and neck squamous cell carcinoma patients included in ProfiLER study and who underwent a curative radiotherapy were screened. Univariate and Cox multivariate analyses were performed to explore the relationships between molecular abnormalities, infield relapse and complete tumor response after radiation.

RESULTS

One hundred and forty-three patients were analyzed. PIK3CA mutation and genomic instability of MAP kinases pathway were found to be prognostic factors of loco-regional relapse in multivariate analysis with respectively HR 0.33, 95% CI 0.13-0.83, p = 0.005 and HR 0.61, 95% CI 0.38-0.96, p = 0.025. Instability of apoptosis pathway was found to be a prognostic factor of complete response after radiotherapy with HR 0.24, 95% CI 0.07-0.88, p = 0.04.

CONCLUSION

This sub analysis suggests that PIK3CA mutation, variation of copy number of MAP kinases and apoptosis pathways play a significant role in the radioresistance phenomenon.

Cell-free DNA comparative analysis of the genomic landscape of first-line hormone receptor-positive metastatic breast cancer from the US and China

PURPOSE

Meaningful comparison of mutational landscapes across ethnic groups requires the use of standardized platform technology. We have used a harmonized NGS-based liquid biopsy assay to explore the differential genomic landscape of patients with initially hormone receptor-positive (HR+), HER2-negative MBC of first line metastasis or primary Stage IV at diagnosis from the United States (US) and China (CN).

METHODS

Plasma circulating tumor DNA (ctDNA) from 27 US patients and 65 CN patients was sequenced using the harmonized CLIA-certified, 152-gene PredicineCare™ liquid biopsy assay. Kaplan-Meier survival analysis was performed to analyze the correlation between genomic alterations and progression-free survival (PFS), and p-values were calculated using the log-rank test.

RESULTS

All patients in the CN cohort received chemotherapy and/or hormonal therapy, while 85.2% (23/27) patients in the US cohort received hormonal therapy plus CDK4/6 inhibitors. Mutations were detected in 23 of 27 (85%) US patients and 54 of 65 (83%) CN patients. The prevalence of AKT1 (P = 0.008) and CDH1 (P = 0.021) alterations were both higher in the US vs. CN cohort. In addition, FGFR1 amplification were more frequent in the CN vs. US cohort (P = 0.048). PTEN deletions (P = 0.03) and ESR1 alterations (P = 0.02) were associated with shorter PFS in the CN cohort, neither of these associations were observed in the US cohort. Interestingly, a reduced association between PTEN deletion and PFS was observed in patients receiving CDK4/6 inhibitor treatment.

CONCLUSION

The differential prevalence of ctDNA-based alterations such as FGFR1, AKT1, and CDH1 was observed in initially HR+/HER2- MBC patients in the US vs. CN. In addition, the association of PTEN deletions with shorter PFS was found in the CN but not the US cohort. The differential genomic landscapes across the two ethnic groups may reflect biologic differences and clinical implications.

Targeted Therapy as a Potential De-Escalation Strategy in Locally Advanced HPV-Associated Oropharyngeal Cancer: A Literature Review

The treatment landscape of locally advanced HPV-oropharyngeal squamous cell carcinoma (OPSCC) is undergoing transformation. This is because the high cures rates observed in OPSCC are paired with severe treatment-related, long-term toxicities. These significant adverse effects have led some to conclude that the current standard of care is over-treating patients, and that de-intensifying the regimens may achieve comparable survival outcomes with lower toxicities. Consequently, several de-escalation approaches involving locally advanced OPSCC are underway. These include the reduction of dosage and volume of intensive cytotoxic regimens, as well as elimination of invasive surgical procedures. Such de-intensifying treatments have the potential to achieve efficacy and concurrently alleviate morbidity. Targeted therapies, given their overall safer toxicity profiles, also make excellent candidates for de-escalation, either alone or alongside standard treatments. However, their role in these endeavors is currently limited, because few targeted therapies are currently in clinical use for head and neck cancers. Unfortunately, cetuximab, the only FDA-approved targeted therapy, has shown inferior outcomes when paired with radiation as compared to cisplatin, the standard radio-sensitizer, in recent de-escalation trials. These findings indicate the need for a better understanding of OPSCC biology in the design of rational therapeutic strategies and the development of novel, OPSCC-targeted therapies that are safe and can improve the therapeutic index of standard therapies. In this review, we summarize ongoing research on mechanism-based inhibitors in OPSCC, beginning with the salient molecular features that modulate tumorigenic processes and response, then exploring pharmacological inhibition and pre-clinical validation studies of candidate targeted agents, and finally, summarizing the progression of those candidates in the clinic.

Targeting PI3K/AKT/mTOR Signaling Pathway in Breast Cancer

Breast cancer is the most frequently diagnosed cancer and the primary cause of cancer death in women worldwide. Although early diagnosis and cancer growth inhibition has significantly improved breast cancer survival rate over the years, there is a current need to develop more effective systemic treatments to prevent metastasis. One of the most commonly altered pathways driving breast cancer cell growth, survival, and motility is the PI3K/AKT/mTOR signaling cascade. In the past 30 years, a great surge of inhibitors targeting these key players has been developed at a rapid pace, leading to effective preclinical studies for cancer therapeutics. However, the central role of PI3K/AKT/mTOR signaling varies among diverse biological processes, suggesting the need for more specific and sophisticated strategies for their use in cancer therapy. In this review, we provide a perspective on the role of the PI3K signaling pathway and the most recently developed PI3K-targeting breast cancer therapies.

High frequency of PIK3CA and TERT promoter mutations in fibromatosis-like spindle cell carcinomas

AIMS

Fibromatosis-like spindle cell carcinomas (FLSCCs) are rare metaplastic breast cancers (MBCs) that are characterised by bland spindle cells in a collagenous stroma. Although some MBCs are highly malignant, FLSCCs have indolent behaviour with low potential for lymph node or distant metastasis. Owing to their rarity, there are limited genomic data on FLSCCs. In this study, we analysed the clinicopathological features and molecular characteristics of four FLSCCs to elucidate the pathogenesis of these rare tumours.

METHODS AND RESULTS

Four pure FLSCCs were sequenced by DIAN (Hangzhou Lab) using a 324-gene platform (FoundationOne CDx) with licensed technologies. The results showed that most FLSCCs harboured the pathogenic H1047R mutation in PIK3CA (3/4, 75%) and the -124C>T mutation in the telomerase reverse transcriptase (TERT) promoter (3/4, 75%). No copy number variations were observed in any cases in our study.

CONCLUSIONS

Our study showed that PIK3CA and TERT promoter mutations were common genetic features of FLSCCs. These findings contribute to our understanding of FLSCCs biology.

Spectrum of PIK3CA/AKT mutations across molecular subtypes of triple-negative breast cancer

PURPOSE

The heterogeneity of triple-negative breast cancer (TNBC) confers variable response to chemotherapy that results in poor outcome and relapse. Due to lack of targeted therapy, there is a need to provide molecular classification of TNBC and identify probable therapeutic targets.

METHODS

We classified TNBC into surrogate molecular subtypes by immunohistochemistry and evaluated hotspot mutations (N = 80) in PIK3CA (exon 4, 9, and 20) and AKT1 (exon 2) in TNBC subtypes by Sanger sequencing.

RESULTS

TNBCs were classified into Basal-like 1(BL1) (n = 20, 25%), Mesenchymal (n = 19, 23.75%), Luminal Androgen (LAR) (n = 12, 15%), Basal+Mesenchymal (Mixed type) (n = 10, 12.5%), and unclassified subtype (n = 19, 23.75%). PIK3CA mutations were observed in 16.25% (13/80) TNBC cases. PIK3CA mutations were more frequent in exon 20 (8.7%) than in exon 9 (5%) and exon 4 (2.5%). PIK3CA mutations were frequent in LAR subtype (33.3%) followed by unclassified type (31.5%), Mesenchymal (10.5%), and BL1 (5%) subtypes. Two hotspot mutations were found in AKT1 (T21I, E17K) in mixed and unclassified subtype.

CONCLUSIONS

This study highlights the heterogeneity within TNBCs. Higher frequencies of PIK3CA mutations were noted in LAR subtypes and unclassified type, comparable to their incidence reported in literature in ER-positive tumors. The mutation status can be used as potential biomarker for PI3K inhibitors in TNBC subgroups.

Environmental and sex-specific molecular signatures of glioma causation

Background

The relative importance of genetic and environmental risk factors in gliomagenesis remains uncertain.

Methods

Using whole-exome sequencing data from 1105 adult gliomas, we evaluate the relative contribution to cancer cell lineage proliferation and survival of single-nucleotide mutations in tumors by IDH mutation subtype and sex. We also quantify the contributions of COSMIC cancer mutational signatures to these tumors, identifying possible risk exposures.

Results

IDH-mutant tumors exhibited few unique recurrent substitutions—all in coding regions, while IDH wild-type tumors exhibited many substitutions in non-coding regions. The importance of previously reported mutations in IDH1/2, TP53, EGFR, PTEN, PIK3CA, and PIK3R1 was confirmed; however, the largest cancer effect in IDH wild-type tumors was associated with mutations in the low-prevalence BRAF V600E. Males and females exhibited mutations in a similar set of significantly overburdened genes, with some differences in variant sites—notably in the phosphoinositide 3-kinase (PI3K) pathway. In IDH-mutant tumors, PIK3CA mutations were located in the helical domain for females and the kinase domain for males; variants of import also differed by sex for PIK3R1. Endogenous age-related mutagenesis was the primary molecular signature identified; a signature associated with exogenous exposure to haloalkanes was identified and noted more frequently in males.

Conclusions

Cancer-causing mutations in glioma primarily originated as a consequence of endogenous rather than exogenous factors. Mutations in helical vs kinase domains of genes in the phosphoinositide 3-kinase (PI3K) pathway are differentially selected in males and females. Additionally, a rare environmental risk factor is suggested for some cases of glioma—particularly in males.

Reconciling the Biological and Transcriptional Variability of Hepatoblastoma with Its Mutational Uniformity

Simple Summary

Hepatoblastoma (HB), the most common form of childhood liver cancer, is associated with dual mutation and/or dysregulation of the Wnt/β-catenin and Hippo pathways in ~50% of cases. However, this mutational simplicity cannot explain HB’s biological and histologic diversity. This discussion focuses upon recent work showing that specific β-catenin mutants are key determinants of this HB variability as well as their metabolic and transcriptional signatures. Dysregulation of the anti-oxidant NFE2L2 pathway also contributes to tumorigenesis by being directly transforming in association with either of the other two factors. The transcriptional overlap of tumors generated by pairs of factors identifies crucial targets that likely mediate HB tumorigenesis, behavior and appearance.

Abstract

Hepatoblastoma (HB), the most common childhood liver cancer, is associated with seven distinct histologic subtypes and variable degrees of clinical aggressiveness and presentation. Yet it is among the least genomically altered tumors known, with about half of HBs showing mutation and/or dysregulation of the Wnt/β-catenin and Hippo pathways. This raises the question of how this mutational simplicity can generate such biological and histologic complexity. Recent work shows that the identity of the underlying β-catenin mutation is a major contributor. Mutation or over-expression of the NFE2L2/NRF2 transcription factor, previously thought only to promote anti-oxidant responses, has also recently been shown to accelerate the growth of HBs generated by mutations in the Wnt/β-catenin and Hippo pathways while imparting novel features such as the tumor-associated cysts and necrosis. Moreover, patient-associated NFE2L2 mutations are overtly transforming when co-expressed with either mutant β-catenin or a Hippo pathway effector. The finding that tumorigenesis can be driven by any two arms of the β-catenin/Hippo/NFE2L2 axis has permitted the identification of a small subset of coordinately regulated tumor-specific transcripts, some of whose levels correlate with inferior long-term outcomes in HB and other cancers. Collectively, these findings begin to provide for more refined and molecularly based classification, survival algorithms and design of chemotherapeutic regimens.

Role of Alpelisib in the Treatment of PIK3CA-Mutated Breast Cancer: Patient Selection and Clinical Perspectives

The PI3K/AKT/mTOR pathway has long been known to play a major role in the growth and survival of cancer cells. Breast tumors often harbor PIK3CA gene alterations, which therefore constitute a rational drug target. However, it has taken many years to demonstrate clinically-relevant efficacy of PI3K inhibition and eventually attain regulatory approvals. As data on PI3K inhibitors continue to mature, this review updates and summarizes the current state of the science, including the prognostic role of PIK3CA alterations in breast cancer; the evolution of PI3K inhibitors; the clinical utility of the first-in-class oral selective PI3Kα inhibitor, alpelisib; PIK3CA mutation detection techniques; and adverse effect management. PIK3CA-mutated breast carcinomas predict survival benefit from PI3K inhibitor therapy. The pan-PI3K inhibitor, buparlisib and the beta-isoform-sparing PI3K inhibitor, taselisib, met efficacy endpoints in clinical trials, but pictilisib did not; moreover, poor tolerability of these three drugs abrogated further clinical trials. Alpelisib is better tolerated, with a more manageable toxicity profile; the principal adverse events, hyperglycemia, rash and diarrhea, can be mitigated by intensive monitoring and timely intervention, thereby enabling patients to remain adherent to clinically beneficial treatment. Alpelisib plus endocrine therapy shows promising efficacy for treating postmenopausal women with HR+/HER2- advanced breast cancer. Available evidence supporting using alpelisib after disease progression on first-line endocrine therapy with or without CDK4/6 inhibitors justifies PIK3CA mutation testing upon diagnosing HR+/HER2- advanced breast cancer, which can be done using either tumor tissue or circulating tumor DNA. With appropriate toxicity management and patient selection using validated testing methods, all eligible patients can potentially benefit from this new treatment. Further clinical trials to assess combinations of hormone therapy with PI3K, AKT, mTOR, or CDK 4/6 inhibitors, or studies in men and women with other breast subtypes are ongoing.

Alpelisib in the treatment of metastatic HR+ breast cancer with PIK3CA mutations

Since the US FDA approval of everolimus/exemestane in July 2012, and of the first CDK 4/6 inhibitor, palbociclib, combined with endocrine treatment in February 2015, a third class of therapeutic compounds, the PI3K inhibitors, has been introduced to the arsenal of targeted therapies overcoming endocrine resistance in hormone receptor-positive metastatic breast cancer. Alpelisib (PIQRAY®) is the first of these novel agents yielding promising clinical results, giving an impetus to further development of tailored endocrine anticancer treatments. Herein, we review its pharmacodynamic and pharmacokinetic properties, safety and efficacy data, as well as Phase III SOLAR-1 trial, prompting FDA approval of alpelisib in hormone receptor-positive metastatic breast cancer harboring PIK3CA mutations. Furthermore, implications for clinical use and current research will also be discussed.

Clinical-Pathologic Analysis of Breast Cancer With PIK3CA Mutations in Chinese Women

Purpose:

Mutations of PIK3CA have recently been shown to play an important role in the pathogenesis and progression of breast neoplasms. The prevalence of PIK3CA in Chinese breast cancer patients may be underestimated. Therefore, we investigated the distribution of somatic PIK3CA mutation in Chinese breast cancer patients and explored their role in tumor phenotypes.

Methods:

Mutational analysis of PIK3CA was done in 113 primary breast cancers of Chinese women used Amplification refractory mutation system (ARMS). The relationship of PIK3CA mutations with several clinicopathologic characteristics was analyzed.

Results:

PIK3CA gene mutation was identified in 43(38.05%) cases and has a more significant difference between exon 9 and 20. HER2 gene amplification was 32.6% in 43 cases of PIK3CA mutation, but 37.1% in 70 cases of non-mutation (χ² = 0.245, P > 0.05). There was no significant correlation of the age distribution, lymph node status, histological tumor grading, ER and/or PR and P53 between 2 groups (P > 0.05).

Conclusion:

A high frequency of somatic PIK3CA mutation was detected in Chinese breast cancer patients, especially in exon 20. The relationship between PIK3CA gene mutation and clinical pathological features of breast cancer needs to be further studied in a large series of patients. PIK3CA mutations seem to have the potential to be used in target treatment and as an indicator of prognosis.

The modern views of the clinical, morphological and molecular biological predictors of breast cancer sensitivity to chemotherapy

In the treatment of breast cancer, the neoadjuvant chemotherapy is vitally important and the evaluation of its effectiveness is crucial for determining the further therapy treatment, as well as the prognosis of the disease. This review provides current data of the physical, instrumental, morphological, molecular biology and genetics analysis used for the estimation of the neoadjuvant treatment effectiveness. Thus, review discusses the data concerning association of the disease peculiarities with the efficient therapeutic response to neoadjuvant chemotherapy including characteristics of patients (age, status of regional lymph nodes, presence of the lymphovascular invasion) and tumors (size, histological type, degree of differentiation, severity of the lymphoid tumor infiltration, molecular biological and genetic peculiarities). Particular attention is paid to such a promising predictive marker of the breast cancer response to chemotherapy as the level of tissue hypoxia. This section discusses the currently known mechanisms that might enable the effect of tissue hypoxia on the sensitivity of the tumor to drug treatment. The prospects for the use of a comprehensive analysis of predictive markers of the effectiveness of chemotherapeutic treatment are discussed.

Cell free DNA biology and its involvement in breast carcinogenesis

Liquid biopsy represents a procedure for minimally invasive analysis of non-solid tissue, blood and other body fluids. It comprises a set of analytes that includes circulating tumor cells (CTCs) and circulating free DNA (cfDNA), RNA, long noncoding RNA (lncRNA) and micro RNA (miRNA), as well as extracellular vesicles. These novel analytes represent an alternative tool to complement diagnosis and monitor and predict response to treatment of the tumoral process and may be used for other disease processes such viral and parasitic infection. This review focuses on the biologic and molecular characteristics of cfDNA in general and the molecular changes (mutational and epigenetic) proven useful in oncologic practice for diagnosis, monitoring and treatment of breast cancer specifically.

Reconstructing kinase network topologies from phosphoproteomics data reveals cancer-associated rewiring

Understanding how oncogenic mutations rewire regulatory-protein networks is important for rationalizing the mechanisms of oncogenesis and for individualizing anticancer treatments. We report a chemical phosphoproteomics method to elucidate the topology of kinase-signaling networks in mammalian cells. We identified >6,000 protein phosphorylation sites that can be used to infer >1,500 kinase-kinase interactions and devised algorithms that can reconstruct kinase network topologies from these phosphoproteomics data. Application of our methods to primary acute myeloid leukemia and breast cancer tumors quantified the relationship between kinase expression and activity, and enabled the identification of hitherto unknown kinase network topologies associated with drug-resistant phenotypes or specific genetic mutations. Using orthogonal methods we validated that PIK3CA wild-type cells adopt MAPK-dependent circuitries in breast cancer cells and that the kinase TTK is important in acute myeloid leukemia. Our phosphoproteomic signatures of network circuitry can identify kinase topologies associated with both phenotypes and genotypes of cancer cells.

Adjuvant chemotherapy could not bring survival benefit to HR-positive, HER2-negative, pT1b-c/N0-1/M0 invasive lobular carcinoma of the breast: a propensity score matching study based on SEER database

BACKGROUND

The benefit of adjuvant chemotherapy in invasive lobular carcinoma (ILC) is still unclear. The objective of the current study was to elucidate the effectiveness of adjuvant chemotherapy in hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative, pT1b-c/N0-1/M0 ILC.

METHODS

Based on Surveillance, Epidemiology, and End-Results (SEER) database, we identified original 12,334 HR-positive, HER2-negative, pT1b-c/N0-1/M0 ILC patients, who were then divided into adjuvant chemotherapy group and control group. End-points were overall survival (OS) and breast cancer-specific mortality (BCSM). Aiming to minimize the selection bias of baseline characteristics, Propensity Score Matching (PSM) method was used.

RESULTS

In a total of 12,334 patients with HR-positive, HER2-negative, pT1b-c/N0-1/M0 ILC, 1785 patients (14.5%) were allocated into adjuvant chemotherapy group and 10,549 (85.5%) into control group. Used PSM, the 1785 patients in adjuvant chemotherapy group matched to the 1785 patients in control group. By Kaplan-Meier survival analyses, we observed no beneficial effect of adjuvant chemotherapy on OS in both original samples (P = 0.639) and matched samples (P = 0.962), however, ineffective or even contrary results of adjuvant chemotherapy on BCSM both in original samples (P = 0.001) and in matched samples (P = 0.002). In both original and matched multivariate Cox models, we observed ineffectiveness of adjuvant chemotherapy on OS (hazard ratio (HR) for overall survival = 0.82, 95% confidence interval (CI) [0.62-1.09]; P = 0.172 and HR = 0.90, 95%CI [0.65-1.26]; P = 0.553, respectively), unexpectedly promoting effect of adjuvant chemotherapy on BCSM (HR = 2.33, 95%CI [1.47-3.67]; P = 0.001 and HR = 2.41, 95%CI [1.32-4.39]; P = 0.004, respectively). Standard surgery was beneficial to the survival of patients. Lymph node metastasis was detrimental to survival and radiotherapy brought survival benefit in original samples, but two issues had unobvious effect in matched samples.

CONCLUSION

In this study, adjuvant chemotherapy did not improve survival for patients with HR-positive, HER2-negative pT1b-c/N0-1/M0 ILC.

Response of metastatic mouse invasive lobular carcinoma to mTOR inhibition is partly mediated by the adaptive immune system

Effective treatment of invasive lobular carcinoma (ILC) of the breast is hampered by late detection, invasive growth, distant metastasis, and poor response to chemotherapy. Phosphoinositide 3-kinase (PI3K) signaling, one of the major druggable oncogenic signaling networks, is frequently activated in ILC. We investigated treatment response and resistance to AZD8055, an inhibitor of mammalian target of rapamycin (mTOR), in the K14-cre;Cdh1^Flox/Flox;Trp53^Flox/Flox (KEP) mouse model of metastatic ILC. Inhibition of mTOR signaling blocked the growth of primary KEP tumors as well as the progression of metastatic disease. However, primary tumors and distant metastases eventually acquired resistance after long-term AZD8055 treatment, despite continued effective suppression of mTOR signaling in cancer cells. Interestingly, therapeutic responses were associated with increased expression of genes related to antigen presentation. Consistent with this observation, increased numbers of tumor-infiltrating major histocompatibility complex class II-positive (MHCII+) immune cells were observed in treatment-responsive KEP tumors. Acquisition of treatment resistance was associated with loss of MHCII+ cells and reduced expression of genes related to the adaptive immune system. The therapeutic efficacy of mTOR inhibition was reduced in Rag1^−/- mice lacking mature T and B lymphocytes, compared to immunocompetent mice. Furthermore, therapy responsiveness could be partially rescued by transplanting AZD8055-resistant KEP tumors into treatment-naïve immunocompetent hosts. Collectively, these data indicate that the PI3K signaling pathway is an attractive therapeutic target in invasive lobular carcinoma, and that part of the therapeutic effect of mTOR inhibition is mediated by the adaptive immune system.

PIK3CA gene mutations in the helical domain correlate with high tumor mutation burden and poor prognosis in metastatic breast carcinomas with late-line therapies

Nearly half of metastatic breast cancers (MBC) have genetic aberrations in the PI3K/AKT pathway. To investigate the distinct effect of these aberrations on MBC, 193 MBC patients who progressed after the early line (≤2) salvage treatment voluntarily received next generation sequencing (NGS) for a panel of 1,021 genes. 93 (48%) patients had genetic aberrations in the PI3K/AKT pathway. The number of patients with PIK3CA mutations in kinase domain (KD), helical domain (HD) and other domain (OD), were 36 (18.7%), 26 (13.5%), 10 (5.2%), respectively. 21 (10.9%) patients had mutations in PI3K/AKT pathway genes other than PIK3CA (P/A). Compared to PI3K/AKT-wild type (WT) patients, PIK3CA-HD patients had a significantly shorter progression-free survival (PFS) (Logrank p-value < 0.0001). PIK3CA-KD, PIK3CA-OD and other P/A mutations showed similar PFS to WT patients (Logrank p-value = 0.63). PIK3CA-HD patients had a distinct ctDNA mutation profile to patients with other PI3K/AKT mutations. PIK3CA-HD patients had a higher rate of FGFR and NF1 aberrations. In addition, more PIK3CA-HD carriers were TMB-high. Cox regression analyses suggested that PIK3CA-HD mutations, FGFR aberrations and high TMB were all significant risk factors for poor PFS. In conclusion, future research needs to focus more on the treatment strategies targeting PIK3CA-HD mutations.

PIK3CA Gene Mutations in Solid Malignancies: Association with Clinicopathological Parameters and Prognosis

Phosphoinositide kinases (PIKs) are a group of lipid kinases that are important upstream activators of various significant signaling pathways. Hyperactivation of the PI3K/AKT/mTOR pathways—either via mutations or genomic amplification—confers key oncogenic activity, essential for the development and progression of several solid tumors. Alterations in the PIK3CA gene are associated with poor prognosis of solid malignancies. Although the literature reports contradictory prognostic values of PIK3CA in aggressive cancers, most of the available data highlight the important role of PIK3CA mutation in mediating tumorigenesis via increased signaling of the PI3K/AKT/mTOR survival pathway. Several inhibitors of PI3K/AKT/mTOR pathways are investigated as potential therapeutic options in solid malignancies. This article reviews the role of PIK3CA mutations and inhibitors of PI3K/AKT/mTOR pathways in major cancer types and examines its association with clinicopathological parameters and prognosis.

Overview of the relevance of PI3K pathway in HR-positive breast cancer

One of the hallmarks of hormone receptor (HR)-positive breast cancer is its dependence on the phosphatidylinositol-3-kinase (PI3K) pathway. Here, we review the epidemiologic, functional, and pharmacologic interactions between oncogenic PI3K and the estrogen receptor (ER). We discuss the epidemiology of PI3K pathway alterations, mechanisms of resistance to PI3K inhibitors, and the current mechanistic landscape of crosstalk between PI3K and ER, which provide the rationale for dual ER and PI3K inhibition and is now a standard of care in the treatment of ER+ PIK3CA-mutant metastatic breast cancer. We outline newer studies in this field that delineate the clinically relevant overlaps between PI3K and parallel signaling pathways, insulin signaling, and ER epigenetic modifiers. We also identify several caveats with the current data and propose new strategies to overcome these bottlenecks.

The Prognostic Significance of Phosphatase and Tensin Homolog Loss in Breast Cancer

AIM

This study aims to determine the prognostic significance of phosphatase and tensin homolog (PTEN) loss in breast cancer.

METHODS

We conducted a meta-analysis study. Sample of this study were research articles that evaluated PTEN loss and prognosis in breast cancer patients. We searched for relevant studies published in PubMed and Proquest from January 2010 to July 2018. We reviewed studies that examined the association between immunohistochemical expression of PTEN and breast cancer prognosis using meta-analysis methods. Pooled risk ratios (RR) were calculated using fixed and random-effect models. Data were processed using Review Manager 5.3 (RevMan 5.3).

RESULTS

There were 7 studies conducted a systematic review then continued to evaluate the association of PTEN loss and breast cancer prognosis by meta-analysis. There was a significant association of PTEN loss with poor prognosis of breast cancer (RR = 0.76 [95% CI 0.59-0.98 p <0.07), and there was not any significant publication bias for studies included.

CONCLUSION

This study confirmed PTEN loss is an important independent factor for breast cancer prognosis.

β-Catenin mutations as determinants of hepatoblastoma phenotypes in mice

Hepatoblastoma (HB) is the most common pediatric liver cancer. Although long-term survival of HB is generally favorable, it depends on clinical stage, tumor histology, and a variety of biochemical and molecular features. HB appears almost exclusively before the age of 3 years, is represented by seven histological subtypes, and is usually associated with highly heterogeneous somatic mutations in the catenin β1 (CTNNB1) gene, which encodes β-catenin, a Wnt ligand-responsive transcriptional co-factor. Numerous recurring β-catenin mutations, not previously documented in HB, have also been identified in various other pediatric and adult cancer types. Little is known about the underlying factors that determine the above HB features and behaviors or whether non-HB-associated β-catenin mutations are tumorigenic when expressed in hepatocytes. Here, we investigated the oncogenic properties of 14 different HB- and non-HB-associated β-catenin mutants encoded by Sleeping Beauty vectors following their delivery into the mouse liver by hydrodynamic tail-vein injection. We show that all β-catenin mutations, as well as WT β-catenin, are tumorigenic when co-expressed with a mutant form of yes-associated protein (YAP). However, tumor growth rates, histologies, nuclear-to-cytoplasmic partitioning, and metabolic and transcriptional landscapes were strongly influenced by the identities of the β-catenin mutations. These findings provide a context for understanding at the molecular level the notable biological diversity of HB.

Nuclease-Assisted Minor Allele Enrichment Using Overlapping Probes-Assisted Amplification-Refractory Mutation System: An Approach for the Improvement of Amplification-Refractory Mutation System-Polymerase Chain Reaction Specificity in Liquid Biopsies

Allele-specific polymerase chain reaction (PCR) (amplification-refractory mutation system, ARMS) is one of the most commonly used methods for mutation detection. However, a main limitation of ARMS-PCR is the false positive results obtained due to nonspecific priming that can take place with wild-type (WT) DNA, which often precludes detection of low-level mutations. To improve the analytical specificity of ARMS, we present here a new technology, NAPA: NaME-PrO-assisted ARMS, that overcomes the ARMS deficiency by adding a brief enzymatic step that reduces wild-type alleles just prior to ARMS. We performed this technology for the simultaneous detection of two hot-spot PIK3CA mutations (E545 K and H1047R) in circulating tumor cells (CTCs) and cell free DNA (cfDNA). The developed protocol could simultaneously detect mutation-allelic-frequency of 0.5% for PIK3CA exon 9 (E545 K) and 0.1% for PIK3CA exon 20 (H1047R) with high specificity. We further compared the developed NAPA assay with (a) ddPCR considered as the gold standard and (b) our previous assay based on the combination of allele-specific, asymmetric rapid PCR, and melting analysis. Our data show that the newly developed NAPA assay gives consistent results with both these assays (p = 0.001). The developed assay resolves the false positive signals issue derived through classic ARMS-PCR and provides an ideal combination of speed, accuracy, and versatility and should be easily applicable in routine diagnostic laboratories.

PIK3CA hotspot mutations in circulating tumor cells and paired circulating tumor DNA in breast cancer: a direct comparison study

Liquid biopsy analysis, mainly based on circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA), provides an extremely powerful tool for the molecular profiling of cancer patients in real time. In this study, we directly compared PIK3CA hotspot mutations (E545K, H1047R) in EpCAM‐positive CTCs and paired plasma‐ctDNA in breast cancer (BrCa). PIK3CA hotspot mutations in CTCs and ctDNA were analyzed using our previously developed highly sensitive (0.05%), specific, and validated assay in plasma‐ctDNA from 77 early and 73 metastatic BrCa patients and 40 healthy donors. We further analyzed and directly compared PIK3CA hotspot mutations in DNAs isolated from CellSearch^® cartridges (CTCs) and paired plasma‐ctDNA, in 56 cases of early and 27 cases of metastatic breast cancer, and 16 corresponding primary tumors. In plasma‐ctDNA,PIK3CA hotspot mutations were identified in 30/77(39.0%) early and 35/73(47.9%) metastatic BrCa cases; none (0/40, 0%) of the healthy donors’ plasma‐ctDNA samples were positive. Our direct comparison study in DNAs isolated from CellSearch^® cartridges (CTCs) and paired plasma‐ctDNA from the same blood draws has shown a lack of concordance in early BrCa (27/56, 48.2%), while the concordance in the metastatic setting was higher (18/27, 66.6%). Our results were validated by ddPCR methodology, and the concordance between our assay and ddPCR for PIK3CA E545K hotspot mutation was 30/37 (81.1%). In many cases, PIK3CA hotspot mutations were detected in samples found to be negative for CTCs in CellSearch^®. Our data demonstrated for the first time that (a) PIK3CA hotspot mutations are present at high frequencies in CTCs isolated from CellSearch^® cartridges and paired plasma‐ctDNA both in early and metastatic BrCa, (b) the detection and concordance of PIK3CA hotspot mutations between plasma‐ctDNA and CTCs are higher in the metastatic setting, (c) PIK3CA mutational status significantly changes after therapeutic intervention, and (d) PIK3CA mutation detection in CTCs and plasma‐ctDNA provides complementary information.

Helical and kinase domain mutations of PIK3CA, and their association with hormone receptor expression in breast cancer

Breast cancer is one of the major causes of female morbidity and mortality, accounting for ~25% of the total cancer cases in women. Phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic α subunit (PIK3CA) mutations serve a major role in downstream signaling of receptor tyrosine kinases. The present study aimed to elucidate the frequency of exon 9 and 20 mutations of PIK3CA and their role in disease progression. A total of 118 tumor samples from confirmed breast cancer patients were collected from the histopathology laboratory at King Fahd Hospital of the University (Al-Khobar, Saudi Arabia). Sanger sequencing was performed on extracted DNA to identify the mutations on exons 9 and 20 of PIK3CA. The results were further validated by competitive allele-specific TaqMan polymerase chain reaction. Three mutations, namely E542K and E545K within exon 9, and H1047R within exon 20, were observed in 25 patients (21.2%). Among these, 18 patients carried the H1047R mutation of the kinase domain, while the remaining 7 patients carried mutations in the helical domain. PIK3CA mutations were associated with the estrogen receptor-positive/progesterone receptor-positive (ER⁺/PR⁺) group of tumors in contrast to the ER⁻/PR⁻ group (P=0.021). Furthermore, it was observed that the PIK3CA mutation was associated with a poor disease prognosis. Taken together, the current study emphasized the potential of PIK3CA mutations as an important biomarker for breast cancer classification and the possible use of PIK3CA inhibitor as targeted therapy for breast cancer.

PIK3CA hotspot mutations in circulating tumor cells and paired circulating tumor DNA in breast cancer: a direct comparison study

Liquid biopsy analysis, mainly based on circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA), provides an extremely powerful tool for the molecular profiling of cancer patients in real time. In this study, we directly compared PIK3CA hotspot mutations (E545K, H1047R) in EpCAM-positive CTCs and paired plasma-ctDNA in breast cancer (BrCa). PIK3CA hotspot mutations in CTCs and ctDNA were analyzed using our previously developed highly sensitive (0.05%), specific, and validated assay in plasma-ctDNA from 77 early and 73 metastatic BrCa patients and 40 healthy donors. We further analyzed and directly compared PIK3CA hotspot mutations in DNAs isolated from CellSearch^® cartridges (CTCs) and paired plasma-ctDNA, in 56 cases of early and 27 cases of metastatic breast cancer, and 16 corresponding primary tumors. In plasma-ctDNA, PIK3CA hotspot mutations were identified in 30/77(39.0%) early and 35/73(47.9%) metastatic BrCa cases; none (0/40, 0%) of the healthy donors' plasma-ctDNA samples were positive. Our direct comparison study in DNAs isolated from CellSearch^® cartridges (CTCs) and paired plasma-ctDNA from the same blood draws has shown a lack of concordance in early BrCa (27/56, 48.2%), while the concordance in the metastatic setting was higher (18/27, 66.6%). Our results were validated by ddPCR methodology, and the concordance between our assay and ddPCR for PIK3CA E545K hotspot mutation was 30/37 (81.1%). In many cases, PIK3CA hotspot mutations were detected in samples found to be negative for CTCs in CellSearch^® . Our data demonstrated for the first time that (a) PIK3CA hotspot mutations are present at high frequencies in CTCs isolated from CellSearch^® cartridges and paired plasma-ctDNA both in early and metastatic BrCa, (b) the detection and concordance of PIK3CA hotspot mutations between plasma-ctDNA and CTCs are higher in the metastatic setting, (c) PIK3CA mutational status significantly changes after therapeutic intervention, and (d) PIK3CA mutation detection in CTCs and plasma-ctDNA provides complementary information.

Mutation of chromatin regulators and focal hotspot alterations characterize human papillomavirus-positive oropharyngeal squamous cell carcinoma

BACKGROUND

Human papillomavirus (HPV)-associated oropharyngeal cancer is a disease clinically and biologically distinct from smoking-related head and neck squamous cell carcinoma (HNSCC). Despite its rapidly increasing incidence, the mutational landscape of HPV+ oropharyngeal squamous cell carcinoma (OPSCC) remains understudied.

METHODS

This article presents the first mutational analysis of the 46 HPV+ OPSCC tumors within the newly expanded cohort of 530 HNSCC tumors from The Cancer Genome Atlas. A separate exome sequencing analysis was also performed for 46 HPV+ OPSCCs matched to their normal lymphocyte controls from the Johns Hopkins University cohort.

RESULTS

There was a strikingly high 33% frequency of mutations within genes associated with chromatin regulation, including mutations in lysine methyltransferase 2C (KMT2C), lysine methyltransferase 2D (KMT2D), nuclear receptor binding SET domain protein 1 (NSD1), CREB binding protein (CREBBP), E1A-associated protein p300 (EP300), and CCCTC-binding factor (CTCF). In addition, the commonly altered genes phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit α (PIK3CA) and fibroblast growth factor receptor 3 (FGFR3) showed distinct domain-specific hotspot mutations in comparison with their HPV- counterparts. PIK3CA showed a uniquely high rate of mutations within the helicase domain, and FGFR3 contained a predominance of hotspot S249C alterations that were not found in HPV- HNSCC.

CONCLUSIONS

This analysis represents one of the largest studies to date of HPV+ OPSCC and lends novel insight into the genetic landscape of this biologically distinct disease, including a high rate of mutations in histone- and chromatin-modifying genes, which may offer novel therapeutic targets.

The distinct clinicopathological and prognostic implications of PIK3CA mutations in breast cancer patients from Central China

Purpose

The mutation status and prognostic value of PIK3CA in breast cancer were widely investigated, which showed significant difference among the patients from vast areas around the world. In this study, the frequency, distribution, bias, and burden of PIK3CA mutations and their relationships with clinicopathologic variables and prognostic significances were investigated in the breast cancer patients from Central China.

Materials and methods

Somatic mutations in exon 9 and exon 20 of PIK3CA gene were analyzed using Sanger sequencing combining with targeted next generation sequencing in 494 breast cancer patients from Central China. The correlations between PIK3CA mutations and clinicopathological characteristics and the prognostic values of multiple PIK3CA mutation statuses were evaluated.

Results

PIK3CA mutations were found in 38% of the patients and associated with estrogen receptor-positive, progesterone receptor-positive, low Ki67 labeling index, and luminal/human epidermal growth factor receptor 2-enriched subtypes. Meanwhile, the prognosis of the total patients and the patients in old diagnostic age, progesterone receptor-negative, low Ki67 labeling index, and luminal/human epidermal growth factor receptor 2-enriched subgroups was significantly related to PIK3CA mutations. Most interestingly, the distribution, bias, and burden of PIK3CA mutations were correlated with different clinical, pathological, and molecular features as well as distinct prognostic implications in multiple breast cancer subgroups.

Conclusion

The frequency, distribution, bias, and burden of PIK3CA mutations were associated with various clinical, pathological, and molecular characteristics in the breast cancer patients from Central China. These different mutation statuses can be used as potential indicators of prognosis in multiple breast cancer subgroups.

PIK3CA mutation is a favorable prognostic factor in esophageal cancer: molecular profile by next-generation sequencing using surgically resected formalin-fixed, paraffin-embedded tissue

Background

Practical and reliable genotyping procedures with a considerable number of samples are required not only for risk-adapted therapeutic strategies, but also for stratifying patients into future clinical trials for molecular-targeting drugs. Recent advances in mutation testing, including next-generation sequencing, have led to the increased use of formalin-fixed paraffin-embedded tissue. We evaluated gene alteration profiles of cancer-related genes in esophageal cancer patients and correlated them with clinicopathological features, such as smoking status and survival outcomes.

Methods

Surgically resected formalin-fixed, paraffin-embedded tissue was collected from 135 consecutive patients with esophageal cancer who underwent esophagectomy. Based on the assessment of DNA quality with a quantitative PCR-based assay, uracil DNA glycosylase pretreatment was performed to ensure quality and accuracy of amplicon-based massively parallel sequencing. Amplicon-based massively parallel sequencing was performed using the Illumina TruSeq® Amplicon Cancer Panel. Gene amplification was detected by quantitative PCR-based assay. Protein expression was determined by automated quantitative fluorescent immunohistochemistry.

Results

Data on genetic alterations were available for 126 patients. The median follow-up time was 1570 days. Amplicon-based massively parallel sequencing identified frequent gene alterations in TP53 (66.7%), PIK3CA (13.5%), APC (10.3%), ERBB4 (7.9%), and FBXW7 (7.9%). There was no association between clinicopathological features or prognosis with smoking status. Multivariate analyses revealed that the PIK3CA mutation and clinical T stage were independent favorable prognostic factors (hazard ratio 0.34, 95% confidence interval: 0.12–0.96, p = 0.042). PIK3CA mutations were significantly associated with APC alterations (p = 0.0007) and BRAF mutations (p = 0.0090).

Conclusions

Our study provided profiles of cancer-related genes in Japanese patients with esophageal cancer by next-generation sequencing using surgically resected formalin-fixed, paraffin-embedded tissue, and identified the PIK3CA mutation as a favorable prognosis biomarker.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4733-7) contains supplementary material, which is available to authorized users.

Tumor PIK3CA Genotype and Prognosis in Early-Stage Breast Cancer: A Pooled Analysis of Individual Patient Data

Purpose Phosphatidylinositol-4, 5-bisphosphate 3-kinase catalytic subunit alpha ( PIK3CA) mutations are frequently observed in primary breast cancer. We evaluated their prognostic relevance by performing a pooled analysis of individual patient data. Patients and Methods Associations between PIK3CA status and clinicopathologic characteristics were tested by applying Cox regression models adjusted for age, tumor size, nodes, grade, estrogen receptor (ER) status, human epidermal growth factor receptor 2 (HER2) status, treatment, and study. Invasive disease-free survival (IDFS) was the primary end point; distant disease-free survival (DDFS) and overall survival (OS) were also assessed, overall and by breast cancer subtypes. Results Data from 10,319 patients from 19 studies were included (median OS follow-up, 6.9 years); 1,787 patients (17%) received chemotherapy, 4,036 (39%) received endocrine monotherapy, 3,583 (35%) received both, and 913 (9%) received none or their treatment was unknown. PIK3CA mutations occurred in 32% of patients, with significant associations with ER positivity, increasing age, lower grade, and smaller size (all P < .001). Prevalence of PIK3CA mutations was 18%, 22%, and 37% in the ER-negative/HER2-negative, HER2-positive, and ER-positive/HER2-negative subtypes, respectively. In univariable analysis, PIK3CA mutations were associated with better IDFS (HR, 0.77; 95% CI, 0.71 to 0.84; P < .001), with evidence for a stronger effect in the first years of follow-up (0 to 5 years: HR, 0.73; 95% CI, 0.66 to 0.81; P < .001; 5 to 10 years: HR, 0.82; 95% CI, 0.68 to 0.99; P = .037); > 10 years: (HR, 1.15; 95% CI, 0.84 to 1.58; P = .38; P heterogeneity = .02). In multivariable analysis, PIK3CA genotype remained significant for improved IDFS ( P = .043), but not for the DDFS and OS end points. Conclusion In this large pooled analysis, PIK3CA mutations were significantly associated with a better IDFS, DDFS, and OS, but had a lesser prognostic effect after adjustment for other prognostic factors.

Clinical outcomes based on multigene profiling in metastatic breast cancer patients

BACKGROUND

Identifying the clinical impact of recurrent mutations can help define their role in cancer. Here, we identify frequent hotspot mutations in metastatic breast cancer (MBC) patients and associate them with clinical outcomes.

PATIENTS AND METHODS

Hotspot mutation testing was conducted in 500 MBC patients using an 11 gene (N = 126) and/or 46 or 50 gene (N = 391) panel. Patients were stratified by hormone receptor (HR) and human epidermal growth factor 2 (HER2) status. Clinical outcomes were retrospectively collected.

RESULTS

Hotspot mutations were most frequently detected in TP53 (30%), PIK3CA (27%) and AKT1 (4%). Triple-negative breast cancer (TNBC) patients had the highest incidence of TP53 (58%) and the lowest incidence of PIK3CA (9%) mutations. TP53 mutation was associated with shorter relapse-free survival (RFS) (median 22 vs 42months; P < 0.001) and overall survival (OS) from diagnosis of distant metastatic disease (median 26 vs 51months; P < 0.001). Conversely, PIK3CA mutation was associated with a trend towards better clinical outcomes including RFS (median 41 vs 30months; P = 0.074) and OS (52 vs 40months; P = 0.066). In HR-positive patients, TP53 mutation was again associated with shorter RFS (median 30 vs 46months; P = 0.017) and OS (median 30 vs 55months; P = 0.001). When multivariable analysis was performed for RFS and OS, TP53 but not PIK3CA mutation remained a significant predictor of outcomes in the overall cohort and in HR-positive patients.

CONCLUSIONS

Clinical hotspot sequencing identifies potentially actionable mutations. In this cohort, TP53 mutation was associated with worse clinical outcomes, while PIK3CA mutation did not remain a significant predictor of outcomes after multivariable analysis.

Evaluation of PIK3CA mutations as a biomarker in Chinese breast carcinomas from Western China

BACKGROUND

PIK3CA gene encodes the p110 α catalytic subunit of the oncoprotein phosphatidylinositol 3-kinase (PI3 K) which regulates many biological processes such as cell proliferation, differentiation, migration and survival through the activation of various signaling pathways.

OBJECTIVE

In this study, we have investigated the possible somatic mutations in PIK3CA gene in invasive ductal breast carcinomas of Chinese women from Western China.

METHODS

Genomic DNA was extracted from the formalin-fixed paraffin-embedded (FFPE) tissue samples. The hotspot mutations in PIK3CA gene of exon 9 and exon 20 were studied by pyrosequencing.

RESULTS

The sequencing identified two hotspot mutations in exon 20 of one cancer samples at p. H1047L (c. 3140A > T) and eight cancer sample at p. H1047R (c. 3140A > G). No mutation in exon 9 of PIK3CA gene was found in these breast cancer tissue samples. PIK3CA mutations showed surprising clinicopathological features in breast cancer patients, as incidence of lymph node invasiveness is increased in the patients with PIK3CA mutation. In addition, all the patients showed tumor size bigger than 3 cm in diameter. It is important that for early detection and early treatment for BC in developing countries or areas like Western China, and for people to provide popularization education using scientific knowledge in cancer fields.

CONCLUSIONS

This study identified PIK3CA mutations in breast carcinoma patients of Western China that will enable a more rapid molecular diagnosis, and provide a stronger rationale evidence for development of precision therapeutic approaches as well as promising therapeutic targets for breast cancer treatment or patient management.

Biomarkers of Everolimus Sensitivity in Hormone Receptor-Positive Breast Cancer

Activation of the mammalian target of rapamycin (mTOR) signaling pathway is an important mechanism of resistance to endocrine therapy in breast cancer. Everolimus, an mTOR inhibitor, has been shown to increase the efficacy of endocrine therapy and overcome resistance to endocrine therapies. Clinical studies have suggested that everolimus combined with endocrine therapy prolongs progression-free survival in hormone receptor-positive breast cancer patients. However, because breast cancer includes a group of highly heterogeneous tumors, patients may have different responses to everolimus. Therefore, finding biomarkers that can predict a patient's positive response or resistance to everolimus is critical. Numerous preclinical studies have shown that PIK3CA/PTEN mutations are predictive of sensitivity to everolimus; however, clinical trials have not confirmed the correlation between mutation status and clinical response. KRAS or BRAF mutations can bypass the phosphatidylinositol 3-kinase pathway; therefore, mutations in KRAS or BRAF may lead to resistance to mTOR inhibitors, and preclinical studies have shown that PIK3CA mutant cells which also contain KRAS mutations are resistant to everolimus. However, there are no clinical data in breast cancer patients to support this conclusion. Therefore, large-scale clinical studies are needed to identify biomarkers of efficacy and resistance to everolimus.