Efficacy and safety of trastuzumab with or without a tyrosine kinase inhibitor for HER2-positive breast cancer: A systematic review and meta-analysis

BackgroundThis study aimed to explore the efficacy and safety of trastuzumab plus tyrosine kinase inhibitors (TKIs) compared with those of trastuzumab monotherapy in patients with human epidermal growth factor receptor (HER2)-positive breast cancer.MethodsThe PubMed, Embase, Cochrane, and Web of Science databases were systematically searched for relevant articles from inception until September 2022. The primary outcomes were overall survival (OS) and progression-free survival (PFS). Subgroup analyses were performed based on disease status, TKI type, and hormone receptor status.ResultsSixteen studies were included in the current analysis. Trastuzumab plus TKI significantly improved OS and PFS compared to trastuzumab monotherapy. In the neoadjuvant setting, trastuzumab plus TKI significantly increased the pathologic complete response (pCR) rate compared to trastuzumab monotherapy. Moreover, a higher objective response rate (ORR) was observed with trastuzumab plus TKI. Patients who received the combination therapy had a higher incidence of discontinuation, all-grade diarrhea, and grade ≥ 3 diarrhea.ConclusionsTrastuzumab plus TKI was better than trastuzumab monotherapy for treating different stages of HER2-positive breast cancer. The safety of trastuzumab plus TKI anti-HER2 therapy was controllable. The different efficacies of TKIs combined with trastuzumab may be related to the mechanism of action of the different TKIs, needing further investigations.     

A systematic analysis of the resistance and sensitivity of HER2YVMA receptor tyrosine kinase mutant to tyrosine kinase inhibitors in HER2-positive lung cancer

Human epidermal growth factor receptor 2 (HER2) has become a well-established target for the treatment of HER2-positive lung cancer. However, a frequently observed in-frame mutation that inserts amino acid quadruplex Tyr776-Val777-Met778-Ala779 at G776 (G776^YVMA) in HER2 kinase domain can cause drug resistance and sensitivity, largely limiting the application of reversible tyrosine kinase inhibitors in lung cancer therapy. A systematic investigation of the intermolecular interactions between the HER2^YVMA mutant and clinical small-molecule inhibitors would help to establish a complete picture of drug response to HER2 G776^YVMA insertion in lung cancer, and to design new tyrosine kinase inhibitors with high potency and selectivity to target the lung cancer-related HER2^YVMA mutant. Here, we combined homology modeling, ligand grafting, structure minimization, molecular simulation and binding affinity analysis to profile a number of tyrosine kinase inhibitors against the G776^YVMA insertion in HER2. It is found that the insertion is far away from HER2 active pocket and thus cannot contact inhibitor ligand directly. However, the insertion is expected to induce marked allosteric effect on some regions around the pocket, including A-loop and hinges connecting between the N- and C-lobes of HER2 kinase domain, which may exert indirect influence to inhibitor binding. Most investigated inhibitors exhibit weak binding strength to both wild-type and mutant HER2, which can be attributed to steric hindrance that impairs ligand compatibility with HER2 active pocket. However, the cognate inhibitor lapatinib and the non-cognate inhibitor bosutinib were predicted to have low affinity for wild-type HER2 but high affinity for HER2^YVMA mutant, which was confirmed by subsequent kinase assay experiments; the inhibitory potencies of bosutinib against wild-type and mutant HER2 were determined to be IC₅₀?>?1000 and =27?nM, respectively, suggesting that the bosutinib might be exploited as a selective inhibitor for mutant over wild-type HER2. Structural examination revealed that formation of additional non-bonded interactions such as hydrogen bonds and hydrophobic contacts with HER2 A-loop region due to G776^YVMA insertion is the primary factor to improve bosutinib affinity upon the mutation.     

Diagnostic and prognostic value of miR-200 family in breast cancer: A meta-analysis and systematic review

BackgroundBreast cancer (BC) is the most common cancer for women all over the world. Great interests have been paid to discover accurate and noninvasive methods for breast cancer diagnosis and prognosis. Although the diagnostic and prognostic value of microRNA-200 (miRNA- 200, miR-200) family has been revealed in many studies, the results were inconsistent. Thus, this meta-analysis aims to assess the overall value of miRNA-200 family in breast cancer diagnosis and prognosis.MethodRelevant studies were searched from the following databases: PubMed, PMC, EMBASE, and ScienceDirect using key words: ("miRNA-200 family" or "miR-141" or "miR-200a" or "miR-200b" or "miR-200c" or "miR-429") and (“HER2” or “Luminal A” or “Luminal B” or “TNBC”) and ("breast cancers" or "breast carcinoma" or "breast malignancy" or "breast tumor"). The sensitivity, specificity, AUC were then calculated to estimate the diagnostic accuracy of the miR-200 family. As for the prognostic value of the miR-200 family, the pooled hazard ratio (HR) was assessed. Heterogeneity among individual studies was also examined by subgroup analyses.ResultA total of 24 articles were included in the meta-analysis. The diagnostic value of miR-200s in BC was presented by the pooled sensitivity was 0.86 (95% CI: 0.83-0.88); the pooled specificity was 0.82 (95% CI: 0.72-0.89); the pooled AUC was 0.931 (95% CI: 0.919-0.942). Besides, expression of miR-200s in metastatic breast cancer has sensitivity, specificity and AUC of 0.70 (95%CI: 0.56-0.81), 0.72 (95%CI: 0.61-0.81), and 0.814 (95%CI: 0.741-0.903), respectively. The meta-analysis then revealed that high expression of miR-200 family corresponded to poor OS (HR: 1.63, 95% CI: 1.03-2.52), poor DFS (HR: 1.55, 95% CI: 0.95-2.56) in BC patients while downregulation of miRNA-200s corresponded to poor OS (HR= 0.84, 95%CI: 0.46-1.63) in TNBC patients and poor OS (HR=0.49; 95%CI: 0.27-0.88) in luminal BC patient.ConclusionThe MiR-200 family has high diagnostic accuracy and can be used as an important biomarker to prognosticate breast cancer.     

HER2 oncogenic function escapes EGFR tyrosine kinase inhibitors via activation of alternative HER receptors in breast cancer cells

Background

The response rate to EGFR tyrosine kinase inhibitors (TKIs) may be poor and unpredictable in cancer patients with EGFR expression itself being an inadequate response indicator. There is limited understanding of the mechanisms underlying this resistance. Furthermore, although TKIs suppress the growth of HER2-overexpressing breast tumor cells, they do not fully inhibit HER2 oncogenic function at physiological doses.

Methodology and Principal Findings

Here we have provided a molecular mechanism of how HER2 oncogenic function escapes TKIs'' inhibition via alternative HER receptor activation as a result of autocrine ligand release. Using both Förster Resonance Energy Transfer (FRET) which monitors in situ HER receptor phosphorylation as well as classical biochemical analysis, we have shown that the specific tyrosine kinase inhibitors (TKIs) of EGFR, AG1478 and Iressa (Gefitinib) decreased EGFR and HER3 phosphorylation through the inhibition of EGFR/HER3 dimerization. Consequent to this, we demonstrate that cleavage of HER4 and dimerization of HER4/HER2 occur together with reactivation of HER3 via HER2/HER3, leading to persistent HER2 phosphorylation in the now resistant, surviving cells. These drug treatment–induced processes were found to be mediated by the release of ligands including heregulin and betacellulin that activate HER3 and HER4 via HER2. Whereas an anti-betacellulin antibody in combination with Iressa increased the anti-proliferative effect in resistant cells, ligands such as heregulin and betacellulin rendered sensitive SKBR3 cells resistant to Iressa.

Conclusions and Significance

These results demonstrate the role of drug-induced autocrine events leading to the activation of alternative HER receptors in maintaining HER2 phosphorylation and in mediating resistance to EGFR tyrosine kinase inhibitors (TKIs) in breast cancer cells, and hence specify treatment opportunities to overcome resistance in patients.     

PIK3CA somatic mutations in breast cancer: Mechanistic insights from Langevin dynamics simulations

Somatic mutations in PIK3CA (phosphatidylinositol-3 kinase, catalytic subunit, alpha isoform) are reported in breast and other human cancers to concentrate at hotspots within its kinase and helical domains. Most of these mutations cause kinase gain of function in vitro and are associated with oncogenicity in vivo. However, little is known about the mechanisms driving tumor development. We have performed computational structural studies on a homology model of wildtype PIK3CA plus recurrent H1047R, H1047L, and P539R mutations, located in the kinase and helical domains, respectively. The time evolution of the structures show that H1047R/L mutants exhibit a larger area of the catalytic cleft between the kinase N- and C-lobes compared with the wildtype that could facilitate the entrance of substrates. This larger area might yield enhanced substrate-to-product turnover associated with oncogenicity. In addition, the H1047R/L mutants display increased kinase activation loop mobility, compared with the wildtype. The P539R mutant forms more hydrogen bonds and salt-bridge interactions than the wildtype, properties that are associated with enhanced thermostability. Mutant-specific differences in the catalytic cleft and activation loop behavior suggest that structure-based mutant-specific inhibitors can be designed for PIK3CA-positive breast cancers.     

Diagnostic and prognostic value of circulating miR-21 for cancer: A systematic review and meta-analysis

Background

MicroRNAs (miRNAs) have been reported to be aberrantly expressed in patients with cancer. Many studies have shown that circulating miRNAs could play potential roles as diagnostic and prognostic biomarkers of cancers. The aim of this meta-analysis is to summarize the role of circulating miR-21 as a biomarker in patients with a variety of carcinomas.

Material and methods

Eligible studies were identified and assessed for quality through multiple search strategies. For diagnostic meta-analysis, the sensitivity, specificity, and other measures of miR-21 in the diagnosis of cancer were pooled using bivariate random-effects approach models. For prognostic meta-analysis, pooled hazard ratios (HRs) of circulating miR-21 for survival were calculated.

Results

A total of 36 studies dealing with various carcinomas were included for the systemic review. Among them, 23 studies were finally enrolled in the global meta-analysis (17 studies for diagnosis and 6 studies for prognosis). For diagnostic meta-analysis, the overall pooled results for sensitivity, specificity, positive likelihood ratio (LRP), negative likelihood ratios (LRN) and diagnostic odds ratio (DOR) were 75.7% (95% CI: 67.1%–82.6%), 79.3% (95% CI: 74.2%–83.5%), 3.65 (95% CI: 2.83–4.70), 0.31 (95% CI: 0.22–0.43), and 11.88 (95% CI: 6.99–20.19), respectively. For prognostic meta-analysis, the pooled HR of higher miR-21 expression in circulation was 2.37 (95% CI: 1.83–3.06, P < 0.001), which could significantly predict poorer survival in general carcinomas. Importantly, subgroup analysis suggested that higher expression of miR-21 correlated with worse overall survival (OS) significantly in carcinomas of digestion system (HR, 5.77 [95% CI: 2.65–12.52]).

Conclusions

Our findings suggest that circulating miR-21 may not suitable to be a diagnostic biomarker, but it has a prognostic value in patients with cancer.     

Tyrosine phosphorylation of HDAC3 by Src kinase mediates proliferation of HER2-positive breast cancer cells

The role of histone deacetylase 3 (HDAC3) is to repress the expression of various genes by eliminating acetyl group from histone. Thus, the regulation of HDAC3 activity is essential to maintain cellular homeostasis. In this study, we found that HDAC3 interacts with c-Src kinase. However, the interaction between HDAC3 and c-Src was previously reported, it has still been ambiguous whether c-Src phosphorylates HDAC3 and affects the function of HDAC3. First, we confirmed that HDAC3 directly binds to c-Src, and c-Src identified to interact with C-terminal domain (277–428 a.a.) of HDAC3. c-Src also phosphorylated three tyrosine sites of HDAC3 at tyrosine 325, 328, and 331. Importantly, wild-type c-Src increases HDAC3 activity, but not mutant c-Src^K298M (kinase inactive form). When these tyrosine residues are all substituted for alanine residues, the deacetylase activity of mutant HDAC3 was abolished. In addition, a proliferation of HER2-positive breast cancer cells expressing phosphorylation deficient mutant HDAC3 is decreased in comparison with control cells. Thus, our findings suggested that phosphorylation of HDAC3 by c-Src kinase regulates the HDAC3 activity and the proliferation of breast cancer cells.     

Immunoproteomics of HER2-positive and HER2-negative breast cancer patients with positive lymph nodes

Identification of more and more novel tumor antigens and autoantibodies will lead to the earlier diagnosis, better prognosis prediction, and more efficient therapy of cancer in the future. Immunoproteomics techniques have successfully been used for finding novel cancer biomarkers in different subgroups of cancer patients. HER2 is a marker for an aggressive breast cancer, particularly in node-positive (NP) cases. The aim of our study was to identify antigens eliciting a humoral immune response in HER2+ and HER2- NP breast cancers by two-dimensional electrophoresis (2D), Western blotting, and mass spectrometry. Sera from 18 women with newly diagnosed NP breast cancer (9 HER2+ and 9 HER2-) and 9 healthy volunteers were individually investigated for the presence of antibodies to MCF7 breast cancer cell line proteome. Reactive spots in 2D blots were matched to stained 2D gels. Twenty-eight of matched spots were identified by mass spectrometry. Among them were LDH-A, glyceraldehydes-3-phosphate dehydrogenase, enolase-α, phosphoglycerate dehydrogenase, proteasome 26S non-ATPase subunit 13, triosephosphate isomerase, hnRNP K, hsp27, hsp90, prohibitin, nucleophosmin, 14-3-3?, PP2A regulatory subunit, and ribonuclease inhibitor-angiogenin. The five former antigens were more commonly reacted with sera from HER2+ cases, and the three latter antigens were more commonly reacted with sera from HER2- cases. Noteworthy, the antigenicity of the 28 spots showed a few differences when SBR3 cell line was used as the source of antigens. Although some of the identified antigens were previously defined as tumor antigens, others were novel. Further investigations for their utilizations as markers for breast cancer diagnosis, progression, and therapy are warranted.     

Prognostic and clinical significance of focal adhesion kinase expression in breast cancer: A systematic review and meta-analysis

BackgroundThe prognostic significance of focal adhesion kinase (FAK) in breast cancer remains controversial. Here, we conducted a meta-analysis to explore the prognostic value of FAK expression in breast cancer.Materials and methodsPossible prognostic significance of protein or mRNA expression of FAK in breast cancer was investigated with searches of electronic databases for relevant publications. Pooled hazard ratios (HRs) and odds ratios (ORs) with 95% confidence intervals (CIs) were extracted from eligible studies.ResultsA total of eight eligible studies which included 2604 participants were analyzed in this meta-analysis. Increased expression of FAK protein was found to significantly correlate with shorter overall survival (OS) (HR = 1.43, 95% CI: 1.12–1.83; P = 0.004), and not with disease-free survival (HR = 1.31, 95% CI: 0.92–1.85; P = 0.14). Elevated FAK protein expression was also associated with negative estrogen receptor (ER) expression (OR, 1.34; 95% CI, 1.06–1.68; P = 0.01), negative progesterone receptor (PR) expression (OR, 1.54; 95% CI, 1.22–1.93; P < 0.001), positive human epidermal growth factor receptor 2 (HER2) expression (OR, 1.64; 95% CI, 1.28–2.09; P < 0.001), triple-negative breast cancer (TNBC) (OR, 1.57; 95% CI, 1.14–2.17; P = 0.006), high nuclear grade (OR, 1.70; 95% CI, 1.05–2.78; P = 0.03), high Ki-67 expression level (OR, 2.87; 95% CI, 1.94–4.24; P < 0.001), and positive p53 status (OR, 2.28; 95% CI, 1.58–3.29; P < 0.001).ConclusionOur meta-analysis identifies an association between increased FAK protein expression and worse OS among breast cancer patients. Moreover, enhanced FAK expression is associated with negative ER expression, negative PR expression, positive HER2 expression, TNBC, high nuclear grade, high Ki-67 expression level, and positive p53 status in breast carcinoma.     

The prognostic value of circulating tumor DNA in patients with melanoma: A systematic review and meta-analysis

BackgroundCirculating tumor DNA (ctDNA) has been investigated as a potential prognostic biomarker to evaluate the therapeutic efficacy and disease progression in melanoma patients, yet results remain inconclusive. The purpose of this study was to illustrate the prognostic value of ctDNA in melanoma.ObjectivesTo describe the clinical prognostic value of ctDNA for melanoma patients.MethodsSearched for eligible articles from Pubmed, Web of Science and Embase. Pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated to evaluate the association between ctDNA at baseline or during treatment and overall survival (OS) and progression-free survival (PFS).ResultsA total of 9 articles were obtained, involving 617 melanoma patients. The pooled HRs revealed that compared with baseline undetectable ctDNA patients, detectable ctDNA was highly correlated with poor OS (HR 2.91, 95% CI: 2.22–3.82; p < 0.001) and PFS (HR 2.75, 95% CI: 1.98–3.83; p < 0.001). A meta-analysis of these adjusted HRs was performed and confirmed that ctDNA collected at baseline was associated with poorer OS/PFS (OS: HR 3.00, 95% CI 2.19–4.11, p < 0.001/PFS: HR 2.68, 95% CI 1.77–4.06, p < 0.001). During treatment, a significant association was shown between ctDNA and poorer OS/PFS (OS: HR 6.26, 95% CI 2.48–15.80, p < 0.001; PFS: HR 4.93, 95% CI 2.36–10.33, p < 0.001).ConclusionInvestigation and application of ctDNA will improve "liquid biopsy" and play a role in early prediction, monitoring disease progression and precise adjusting treatment strategies in melanoma patients.     

Predictive and prognostic impact of TP53 mutations and MDM2 promoter genotype in primary breast cancer patients treated with epirubicin or paclitaxel

Background

TP53 mutations have been associated with resistance to anthracyclines but not to taxanes in breast cancer patients. The MDM2 promoter single nucleotide polymorphism (SNP) T309G increases MDM2 activity and may reduce wild-type p53 protein activity. Here, we explored the predictive and prognostic value of TP53 and CHEK2 mutation status together with MDM2 SNP309 genotype in stage III breast cancer patients receiving paclitaxel or epirubicin monotherapy.

Experimental Design

Each patient was randomly assigned to treatment with epirubicin 90 mg/m² (n = 109) or paclitaxel 200 mg/m² (n = 114) every 3rd week as monotherapy for 4–6 cycles. Patients obtaining a suboptimal response on first-line treatment requiring further chemotherapy received the opposite regimen. Time from last patient inclusion to follow-up censoring was 69 months. Each patient had snap-frozen tumor tissue specimens collected prior to commencing chemotherapy.

Principal Findings

While TP53 and CHEK2 mutations predicted resistance to epirubicin, MDM2 status did not. Neither TP53/CHEK2 mutations nor MDM2 status was associated with paclitaxel response. Remarkably, TP53 mutations (p = 0.007) but also MDM2 309TG/GG genotype status (p = 0.012) were associated with a poor disease-specific survival among patients having paclitaxel but not patients having epirubicin first-line. The effect of MDM2 status was observed among individuals harbouring wild-type TP53 (p = 0.039) but not among individuals with TP53 mutated tumors (p>0.5).

Conclusion

TP53 and CHEK2 mutations were associated with lack of response to epirubicin monotherapy. In contrast, TP53 mutations and MDM2 309G allele status conferred poor disease-specific survival among patients treated with primary paclitaxel but not epirubicin monotherapy.     

A novel mutant PIK3R1EY451delinsD breast cancer patient resistant to HER2-targeted therapy treated with everolimus: a case report

Molecular Biology Reports - Resistance to HER2-targeted therapy is a critical issue in breast cancer that must be addressed immediately. PIK3R1 mutations are more common in Chinese breast cancer...     

Role of E542 and E545 missense mutations of PIK3CA in breast cancer: a comparative computational approach

Recent statistics describe breast cancer as the leading cause of death among women across the world with varied causes and reasons. Lifestyle, diet, genetic and environmental factors introduce their generous contributions towards breast cancer, among which genetic factors have lately become one of the most important aspects in understanding the mechanism. Although various genes have already been reported in causing breast cancer, PIK3CA stands second on the list. Mutations observed in this gene have the ability to trigger the different activities of the cell, thereby bypassing the regular cellular cycle. Among the mutations in PIK3CA, three hotspot mutations were commonly reported, one in the catalytic domain (position HIS1047) and other two in the helical domain (position GLU542 and GLU545). In the helical domain of PIK3CA, the lysine substitution at 542–545 positions was significantly studied in causing breast cancer. To compare the deleterious effect of these mutations, in silico prediction tools along with molecular dynamics simulations and molecular docking approach was initiated to analyse the change in binding landscape upon mutation. In this comparative analysis, we report that the mere existence of mutant E545K can trigger the function of the protein but may not be as harmful as H1047R. Among the two mutations E542K and E545K, the latter shows the most deleterious effect that correlates with the previous reported experimental studies. We assume the results observed in this combinatorial computational study might further pave a better way for providing better treatment procedures.     

The clinical significance and prognostic value of Xenopus kinesin-like protein 2 expressions in human tumors: A systematic review and meta-analysis

Targeting protein for Xenopus kinesin-like protein 2 (TPX2) is a microtubule-associated protein that plays a pivotal part in the formation of spindles. There is accumulating evidence that the expression of TPX2 is upregulated in many kinds of human cancers and that this protein is involved in the occurrence and progression of tumors. The purpose of this meta-analysis was to investigate the relationship between the overexpression of TPX2 and poor prognosis in cancer patients. A total of 18 eligible studies encompassing 3115 patients were included by searching relevant databases. Hazard ratios (HRs) or odds ratios (ORs) with 95% confidence intervals (CIs) were pooled under random-/fixed-effect models. After calculation, the results showed that patients with increased TPX2 expression had a significantly shorter overall survival (HR = 2.21; 95% CI: 1.70–2.86), and disease-free survival (HR = 2.10; 95% CI: 1.67–2.64). In addition, it was found that increased TPX2 expression was significantly associated with TNM stage (OR = 2.17; 95% CI:1.42–3.32), lymph node metastasis (OR = 2.98; 95% CI: 2.28–3.89), distant metastasis (OR = 2.25; 95% CI:1.03–4.92), and vascular invasion (OR = 2.22; 95% CI:1.26–3.91). Nevertheless, there was no significant correlation between increased expression of TPX2 and either gender, tumor differentiation, or tumor size. Thus, we can come to the conclusion that the overexpression of TPX2 is related to poor clinical outcomes and can be used as a biomarker for the prognosis of patients with cancer.     

CA 15-3: a prognostic marker in breast cancer

CA 15-3 (also known as MUC1) is the most widely used serum marker in breast cancer. MUC1 is a large transmembrane glycoprotein which is frequently overexpressed and aberrantly glycosylated in cancer. Physiologically, MUC1 appears to play a role in cell adhesion and the high levels present in cancer may be causally involved in metastasis. At present the main uses of CA 15-3 are in preclinically detecting recurrent breast cancer and monitoring the treatment of patients with advanced breast cancer. In a prospective study of 368 patients we show that patients with high preoperative levels of CA 15-3 (>30.4 U/mL) had a worse outcome than patients with low levels of the marker. In multivariate analysis CA 15-3 as a prognostic marker was independent of both tumor size and nodal status. Furthermore, in multivariate analysis the prognostic impact of CA 15-3 was stronger than that of tumor size and at least as strong as nodal status. CA 15-3 may thus be the first independent prognostic serum marker in breast cancer.     

PIK3CA mutations frequently coexist with RAS and BRAF mutations in patients with advanced cancers

Background

Oncogenic mutations of PIK3CA, RAS (KRAS, NRAS), and BRAF have been identified in various malignancies, and activate the PI3K/AKT/mTOR and RAS/RAF/MEK pathways, respectively. Both pathways are critical drivers of tumorigenesis.

Methods

Tumor tissues from 504 patients with diverse cancers referred to the Clinical Center for Targeted Therapy at MD Anderson Cancer Center starting in October 2008 were analyzed for PIK3CA, RAS (KRAS, NRAS), and BRAF mutations using polymerase chain reaction-based DNA sequencing.

Results

PIK3CA mutations were found in 54 (11%) of 504 patients tested; KRAS in 69 (19%) of 367; NRAS in 19 (8%) of 225; and BRAF in 31 (9%) of 361 patients. PIK3CA mutations were most frequent in squamous cervical (5/14, 36%), uterine (7/28, 25%), breast (6/29, 21%), and colorectal cancers (18/105, 17%); KRAS in pancreatic (5/9, 56%), colorectal (49/97, 51%), and uterine cancers (3/20, 15%); NRAS in melanoma (12/40, 30%), and uterine cancer (2/11, 18%); BRAF in melanoma (23/52, 44%), and colorectal cancer (5/88, 6%). Regardless of histology, KRAS mutations were found in 38% of patients with PIK3CA mutations compared to 16% of patients with wild-type (wt)PIK3CA (p = 0.001). In total, RAS (KRAS, NRAS) or BRAF mutations were found in 47% of patients with PIK3CA mutations vs. 24% of patients wtPIK3CA (p = 0.001). PIK3CA mutations were found in 28% of patients with KRAS mutations compared to 10% with wtKRAS (p = 0.001) and in 20% of patients with RAS (KRAS, NRAS) or BRAF mutations compared to 8% with wtRAS (KRAS, NRAS) or wtBRAF (p = 0.001).

Conclusions

PIK3CA, RAS (KRAS, NRAS), and BRAF mutations are frequent in diverse tumors. In a wide variety of tumors, PIK3CA mutations coexist with RAS (KRAS, NRAS) and BRAF mutations.     

Trastuzumab in the adjuvant treatment of HER2-positive early breast cancer patients: a meta-analysis of published randomized controlled trials

Background

Adjuvant trastuzumab therapy has yielded conflicting results for overall survival, concerns about central nervous system (CNS) metastasis, and questions about optimal schedule. Therefore, we carried out a meta-analysis to assess the benefits of concurrent or sequential trastuzumab with adjuvant chemotherapy for early breast cancer patients with HER2-positive tumors.

Methods

Computerized and manual searches were performed to identify randomized clinical trials comparing adjuvant chemotherapy with or without trastuzumab in HER2-positive early breast cancer patients. Odds ratios were used to estimate the association between the addition of trastuzumab to adjuvant chemotherapy and various survival outcomes. The fixed-effects or random-effects model was used to combine data.

Findings

With six eligible studies identified, this analysis demonstrated that patients with HER2-positive breast cancer derived benefit in disease-free survival, overall survival, locoregional recurrence and distant recurrence (all P<0.001) from the addition of trastuzumab to adjuvant chemotherapy, whereas trastuzumab did worse in CNS recurrence as compared to the control group (P = 0.018). Furthermore, concomitant use of trastuzumab significantly lowered the hazard of death (P<0.001) but bore a higher incidence of CNS recurrence (P = 0.010), while statistical significance failed to be discerned for either overall survival (P = 0.069) or CNS metastasis (P = 0.374) between the sequential and observation arms.

Conclusion

This analysis verifies the efficacy of trastuzumab in the adjuvant setting. Additionally, our findings indirectly corroborate the superiority of concurrent trastuzumab to sequential use and also illuminate that prolonged survival is the possible reason for the higher incidence of CNS with trastuzumab versus observation.