Clustering of HR + /HER2- breast cancer in an Asian cohort is driven by immune phenotypes.

Breast cancer exhibits significant heterogeneity, manifesting in various subtypes that are critical in guiding treatment decisions. This study aimed to investigate the existence of distinct subtypes of breast cancer within the Asian population, by analysing the transcriptomic profiles of 934 breast cancer patients from a Malaysian cohort. Our findings reveal that the HR + /HER2- breast cancer samples display a distinct clustering pattern based on immune phenotypes, rather than conforming to the conventional luminal A-luminal B paradigm previously reported in breast cancers from women of European descent. This suggests that the activation of the immune system may play a more important role in Asian HR + /HER2- breast cancer than has been previously recognized. Analysis of somatic mutations by whole exome sequencing showed that counter-intuitively, the cluster of HR + /HER2- samples exhibiting higher immune scores was associated with lower tumour mutational burden, lower homologous recombination deficiency scores, and fewer copy number aberrations, implicating the involvement of non-canonical tumour immune pathways. Further investigations are warranted to determine the underlying mechanisms of these pathways, with the potential to develop innovative immunotherapeutic approaches tailored to this specific patient population.

TP53 somatic mutations in Asian breast cancer are associated with subtype-specific effects.

BACKGROUND: Recent genomics studies of breast cancer in Asian cohorts have found a higher prevalence of TP53 mutations in Asian breast cancer patients relative to Caucasian patients. However, the effect of TP53 mutations on Asian breast tumours has not been comprehensively studied. METHODS: Here, we report an analysis of 492 breast cancer samples from the Malaysian Breast Cancer cohort where we examined the impact of TP53 somatic mutations in relation to PAM50 subtypes by comparing whole exome and transcriptome data from tumours with mutant and wild-type TP53. RESULTS: We found that the magnitude of impact of TP53 somatic mutations appears to vary between different subtypes. TP53 somatic mutations were associated with higher HR deficiency scores as well as greater upregulation of gene expression pathways in luminal A and luminal B tumours compared to the basal-like and Her2-enriched subtypes. The only pathways that were consistently dysregulated when comparing tumours with mutant and wild-type TP53 across different subtypes were the mTORC1 signalling and glycolysis pathways. CONCLUSION: These results suggest that therapies that target TP53 or other downstream pathways may be more effective against luminal A and B tumours in the Asian population.

Visual-spatial dimension integration in digital pathology education enhances anatomical pathology learning.

Literature review demonstrated a surprising lack of publications on digital e-learning pathology resources for senior medical undergraduates and interns. An interactive Digital Pathology Repository (iDPR) integrating two- and three-dimensional (2D, 3D) high-resolution anatomical pathology images with correlated digital histopathology was developed. The novel iDPR was rigorously evaluated using mixed methods to assess pathology knowledge gains (pre- and post-tests), quality impact analysis (questionnaire), user feedback (focus group discussions) and user visual behaviour (eye gaze tracking analysis of 2D/ 3D images).Exposure to iDPR appeared to improve user pathology knowledge, as observed by significantly increased test scores on topic-related quizzes (n = 69, p < 0.001). In addition, most users were highly satisfied with the key design elements of the iDPR tool. Focus group discussion revealed the iDPR was regarded as a relevant online learning resource, although some minor technical issues were also noted. Interestingly, visual behaviour trends indicated that specific diagnostic pathological lesions could be correctly identified faster in 3D images, when compared to 2D images.The iDPR offers promise and potential in pathology education for senior clinical students and interns, gauging from both qualitative and quantitative positive user feedback. With incorporation of image annotations and interactive functionality, and with further technology development, this would prove a useful tool for diagnostic pathology and telepathology. As images with added visual-spatial dimension can provide enhanced detail and aid more rapid diagnosis, future applications of the iDPR could include virtual reality or holographic images of anatomical pathology specimens.

Germline APOBEC3B deletion increases somatic hypermutation in Asian breast cancer that is associated with Her2 subtype, PIK3CA mutations and immune activation.

A 30-kb deletion that eliminates the coding region of APOBEC3B (A3B) is >5 times more common in women of Asian descent compared to European descent. This polymorphism creates a chimera with the APOBEC3A (A3A) coding region and A3B 3'UTR, and it is associated with an increased risk for breast cancer in Asian women. Here, we explored the relationship between the A3B deletion polymorphism with tumour characteristics in Asian women. Using whole exome and whole transcriptome sequencing data of 527 breast tumours, we report that germline A3B deletion polymorphism leads to expression of the A3A-B hybrid isoform and increased APOBEC-associated somatic hypermutation. Hypermutated tumours, regardless of A3B germline status, were associated with the Her2 molecular subtype and PIK3CA mutations. Compared to nonhypermutated tumours, hypermutated tumours also had higher neoantigen burden, tumour heterogeneity and immune activation. Taken together, our results suggest that the germline A3B deletion polymorphism, via the A3A-B hybrid isoform, contributes to APOBEC mutagenesis in a significant proportion of Asian breast cancers. In addition, APOBEC somatic hypermutation, regardless of A3B background, may be an important clinical biomarker for Asian breast cancers.

Cytotoxic, Anti-Proliferative and Apoptosis Activity of l-Amino Acid Oxidase from Malaysian Cryptelytrops purpureomaculatus (CP-LAAO) Venom on Human Colon Cancer Cells.

The aim of this study is to investigate the potential anti-cancer activity of l-amino acid oxidase (CP-LAAO) purified from the venom of Cryptelytrops purpureomaculatus on SW480 and SW620 human colon cancer cells. Mass spectrometry guided purification was able to identify and purify CP-LAAO. Amino acid variations identified from the partial protein sequence of CP-LAAO may suggest novel variants of these proteins. The activity of the purified CP-LAAO was confirmed with o-phenyldiamine (OPD)-based spectrophotometric assay. CP-LAAO demonstrated time- and dose-dependent cytotoxic activity and the EC50 value was determined at 13 µg/mL for both SW480 and SW620 cells. Significant increase of caspase-3 activity, reduction of Bcl-2 levels, as well as morphological changes consistent with apoptosis were demonstrated by CP-LAAO. Overall, these data provide evidence on the potential anti-cancer activity of CP-LAAO from the venom of Malaysian C. purpureomaculatus for therapeutic intervention of human colon cancer.

Germline APOBEC3B deletion is associated with breast cancer risk in an Asian multi-ethnic cohort and with immune cell presentation.

BACKGROUND: APOBEC3B is a cytosine deaminase implicated in immune response to viral infection, cancer predisposition and carcinogenesis. Germline APOBEC3B deletion is more common in East Asian women and confers a modest risk to breast cancer in both East Asian and Caucasian women. Analysis of tumour samples from women of European descent has shown that germline APOBEC3B deletion is associated with an increased propensity to develop somatic mutations and with an enrichment for immune response-related gene sets. However, this has not been examined in Asian tumour samples, where population differences in genetic and dietary factors may have an impact on the immune system. METHODS: In this study, we determined the prevalence of germline APOBEC3B deletion and its association with breast cancer risk in a cross-sectional hospital-based Asian multi-ethnic cohort of 1451 cases and 1442 controls from Malaysia. We compared gene expression profiles of breast cancers arising from APOBEC3B deletion carriers and non-carriers using microarray analyses. Finally, we characterised the overall abundance of tumour-infiltrating immune cells in breast cancers from TCGA and METABRIC using ESTIMATE and relative frequency of 22 immune cell subsets in breast cancers from METABRIC using CIBERSORT. RESULTS: The minor allelic frequency of APOBEC3B deletion was estimated to be 0.35, 0.42 and 0.16 in female populations of Chinese, Malay and Indian descent, respectively, and that germline APOBEC3B deletion was associated with breast cancer risk with odds ratios of 1.23 (95 % CI: [1.05, 1.44]) for one-copy deletion and 1.38 (95 % CI: [1.10, 1.74]) for two-copy deletion compared to women with no deletion. Germline APOBEC3B deletion was not associated with any clinicopathologic features or the expression of any APOBEC family members but was associated with immune response-related gene sets (FDR q values < 0.05). Analysis of breast cancers from METABRIC revealed breast cancers from APOBEC3B deletion carriers to have significantly higher abundance of tumour-infiltrating immune cells (P < 0.001). CONCLUSIONS: Taken together, our data suggests that tumour-infiltrating immune cells may be an important feature of breast cancers arising in women with APOBEC3B germline deletion, and that this may be of particular interest in Asian women where the germline deletion is more common.

Down-regulation of LPA receptor 5 contributes to aberrant LPA signalling in EBV-associated nasopharyngeal carcinoma.

Undifferentiated nasopharyngeal carcinoma (NPC) is a highly metastatic disease that is consistently associated with Epstein-Barr virus (EBV) infection. In this study, we have investigated the contribution of lysophosphatidic acid (LPA) signalling to the pathogenesis of NPC. Here we demonstrate two distinct functional roles for LPA in NPC. First, we show that LPA enhances the migration of NPC cells and second, that it can inhibit the activity of EBV-specific cytotoxic T cells. Focusing on the first of these phenotypes, we show that one of the LPA receptors, LPA receptor 5 (LPAR5), is down-regulated in primary NPC tissues and that this down-regulation promotes the LPA-induced migration of NPC cell lines. Furthermore, we found that EBV infection or ectopic expression of the EBV-encoded LMP2A was sufficient to down-regulate LPAR5 in NPC cell lines. Our data point to a central role for EBV in mediating the oncogenic effects of LPA in NPC and identify LPA signalling as a potential therapeutic target in this disease.

Establishment and Characterization of an Epstein-Barr Virus-positive Cell Line from a Non-keratinizing Differentiated Primary Nasopharyngeal Carcinoma.

Nasopharyngeal carcinoma (NPC), a cancer that is etiologically associated with the Epstein-Barr virus (EBV), is endemic in Southern China and Southeast Asia. The scarcity of representative NPC cell lines owing to the frequent loss of EBV episomes following prolonged propagation and compromised authenticity of previous models underscores the critical need for new EBV-positive NPC models. Herein, we describe the establishment of a new EBV-positive NPC cell line, designated NPC268 from a primary non-keratinizing, differentiated NPC tissue. NPC268 can undergo productive lytic reactivation of EBV and is highly tumorigenic in immunodeficient mice. Whole-genome sequencing revealed close similarities with the tissue of origin, including large chromosomal rearrangements, while whole-genome bisulfite sequencing and RNA sequencing demonstrated a hypomethylated genome and enrichment in immune-related pathways, respectively. Drug screening of NPC268 together with six other NPC cell lines using 339 compounds, representing the largest high-throughput drug testing in NPC, revealed biomarkers associated with specific drug classes. NPC268 represents the first and only available EBV-positive non-keratinizing differentiated NPC model, and extensive genomic, methylomic, transcriptomic, and drug response data should facilitate research in EBV and NPC, where current models are limited. SIGNIFICANCE: NPC268 is the first and only EBV-positive cell line derived from a primary non-keratinizing, differentiated nasopharyngeal carcinoma, an understudied but important subtype in Southeast Asian countries. This model adds to the limited number of authentic EBV-positive lines globally that will facilitate mechanistic studies and drug development for NPC.

A Case Report of Leptomeningeal Myelomatosis and Rapid Improvement with Regimen Consisting of Daratumumab, Pomalidomide, Vincristine, Procarbazine, and Dexamethasone.

Central nervous system (CNS) involvement in multiple myeloma (MM) (MM-CNS) in the form of leptomeningeal myelomatosis or brain parenchyma plasmacytoma is rare, causing challenges in clinical diagnosis and treatment. We would like to report a case of leptomeningeal myelomatosis and illustrated the challeges. A 61-year-old man was diagnosed with MM with left paravertebral plasmacytoma, R-ISS II with high suspicion of double-hit MM, either biallelic aberrancy of TP53 or del(17p) and IGH aberrancy depending on the definition chosen, treated with lenalidomide-bortezomib-dexamethasone and local radiotherapy, later developed systemic relapse and progression to MM-CNS in the form of leptomeningeal myelomatosis. A modified CNS-based treatment not reported before, consisting of daratumumab, pomalidomide, vincristine, procarbazine, and dexamethasone, brought a rapid clinical improvement and warrants a further study. Incorporation of intrathecal thiotepa into the regimen would likely increase the efficacy.

Proteomic Analysis on Anti-Proliferative and Apoptosis Effects of Curcumin Analog, 1,5-bis(4-Hydroxy-3-Methyoxyphenyl)-1,4-Pentadiene-3-One-Treated Human Glioblastoma and Neuroblastoma Cells.

Curcumin analogs with excellent biological properties have been synthesized to address and overcome the poor pharmacokinetic profiles of curcumin. This study aims to investigate the cytotoxicity, anti-proliferative, and apoptosis-inducing ability of curcumin analog, MS13 on human glioblastoma U-87 MG, and neuroblastoma SH-SY5Y cells, and to examine the global proteome changes in these cells following treatment. Our current findings showed that MS13 induced potent cytotoxicity and anti-proliferative effects on both cells. Increased caspase-3 activity and decreased bcl-2 concentration upon treatment indicate that MS13 induces apoptosis in these cells in a dose- and time-dependent manner. The label-free shotgun proteomic analysis has defined the protein profiles in both glioblastoma and neuroblastoma cells, whereby a total of nine common DEPs, inclusive of glyceraldehyde 3-phosphate dehydrogenase (GAPDH), alpha-enolase (ENO1), heat shock protein HSP 90-alpha (HSP90AA1), Heat shock protein HSP 90-beta (HSP90AB1), Eukaryotic translation initiation factor 5A-1 (EFI5A), heterogenous nuclear ribonucleoprotein K (HNRNPK), tubulin beta chain (TUBB), histone H2AX (H2AFX), and Protein SET were identified. Pathway analysis further elucidated that MS13 may induce its anti-tumor effects in both cells via the common enriched pathways, "Glycolysis" and "Post-translational protein modification." Conclusively, MS13 demonstrates an anti-cancer effect that may indicate its potential use in the management of brain malignancies.

HER2 testing by immunohistochemistry in breast cancer: A multicenter proficiency ring study.

BACKGROUND: Human epidermal growth factor receptor 2 (HER2) over-expression in breast cancer is associated with aggressive tumor behavior and predicts response to targeted therapy. Accurate HER2 result is paramount for optimal patient management. However, routine HER2 immunohistochemistry (IHC) testing are subjected to intra- and inter-laboratory variability. OBJECTIVE: This study aims to determine inter-laboratory variation in HER2 IHC testing through a slide-exchange program between five main reference laboratories. METHOD: A total of 20 breast carcinoma cases with different known HER2 expression and gene status were selected by the central laboratory in five testing rounds. Three unstained tissue sections from each case were sent to participating laboratories, which immunostained and interpreted the HER2 immunohistochemistry result. One of the stained slides was sent to one designated participating laboratory for evaluation. Results were analyzed by the central laboratory. RESULTS: A complete concordance was achieved in six IHC-positive and six IHC-negative cases, its gene status of which was confirmed by in-situ-hybridization (ISH) study. The discordant results were observed in six equivocal cases, one negative case and one positive case with a concordance rate of 50-88.3%. Interestingly, the negative discordant case actually displays tumor heterogeneity. Good inter-observer agreement was achieved for all participating laboratories (k = 0.713-1.0). CONCLUSION: Standardization of HER2 testing method is important to achieve optimum inter-laboratory concordance. Discordant results were seen mainly in equivocal cases. Intra-tumoral heterogeneity may impact the final HER2 IHC scoring. The continuous quality evaluation is therefore paramount to achieve reliable HER2 results.

Characterisation of PALB2 tumours through whole-exome and whole-transcriptomic analyses.

Rare protein-truncating variants (PTVs) in PALB2 confer increased risk to breast cancer, but relatively few studies have reported the characteristics of tumours with PALB2 PTVs. In this study, we describe molecular characteristics of tumours with either germline or somatic alterations in PALB2. DNA from fresh frozen tumour tissues and matched peripheral blood lymphocytes for 560 breast cancer patients was subjected for whole-exome sequencing (WES), and RNA from tumour tissues was subjected to RNA sequencing (RNA-seq). We found six cases with germline and three with somatic protein-truncating variants in PALB2. The characteristics of tumours in patients with PALB2 PTVs were similar to those with BRCA1 and BRCA2 PTVs, having significantly more somatic alterations, and a high proportion of the mutational signature and genomic scar scores characteristic of deficiencies in homologous recombination (HR), compared to tumours arising in non-carriers. Unlike tumours arising in patients with BRCA1 and BRCA2 PTVs, PALB2 tumours did not have high prevalence of TP53 somatic alterations or an enriched immune microenvironment. In summary, PALB2 tumours show the homologous recombination deficiencies characteristic of BRCA1 and BRCA2 tumours, and highlight the potential clinical relevance of PALB2 mutational status in guiding therapeutic choices.

The molecular landscape of Asian breast cancers reveals clinically relevant population-specific differences.

Molecular profiling of breast cancer has enabled the development of more robust molecular prognostic signatures and therapeutic options for breast cancer patients. However, non-Caucasian populations remain understudied. Here, we present the mutational, transcriptional, and copy number profiles of 560 Malaysian breast tumours and a comparative analysis of breast cancers arising in Asian and Caucasian women. Compared to breast tumours in Caucasian women, we show an increased prevalence of HER2-enriched molecular subtypes and higher prevalence of TP53 somatic mutations in ER+ Asian breast tumours. We also observe elevated immune scores in Asian breast tumours, suggesting potential clinical response to immune checkpoint inhibitors. Whilst HER2-subtype and enriched immune score are associated with improved survival, presence of TP53 somatic mutations is associated with poorer survival in ER+ tumours. Taken together, these population differences unveil opportunities to improve the understanding of this disease and lay the foundation for precision medicine in different populations.

Monoamine oxidase A is down-regulated in EBV-associated nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is a highly metastatic cancer that is consistently associated with Epstein-Barr virus (EBV) infection. In this study, we identify for the first time a role for monoamine oxidase A (MAOA) in NPC. MAOA is a mitochondrial enzyme that catalyzes oxidative deamination of neurotransmitters and dietary amines. Depending on the cancer type, MAOA can either have a tumour-promoting or tumour-suppressive role. We show that MAOA is down-regulated in primary NPC tissues and its down-regulation enhances the migration of NPC cells. In addition, we found that EBV infection can down-regulate MAOA expression in both pre-malignant and malignant nasopharyngeal epithelial (NPE) cells. We further demonstrate that MAOA is down-regulated as a result of IL-6/IL-6R/STAT3 signalling and epigenetic mechanisms, effects that might be attributed to EBV infection in NPE cells. Taken together, our data point to a central role for EBV in mediating the tumour suppressive effects of MAOA and that loss of MAOA could be an important step in the pathogenesis of NPC.

Molecular testing for advanced non-small cell lung cancer in Malaysia: Consensus statement from the College of Pathologists, Academy of Medicine Malaysia, the Malaysian Thoracic Society, and the Malaysian Oncological Society.

In the recent years, increased understanding of the molecular profiles of non-small cell lung cancer (NSCLC) has allowed for targeted treatment of actionable genetic mutations. The management of NSCLC now requires multiple molecular tests to guide the treatment strategy. In the light of this, there is a need to establish a molecular testing consensus statement for advanced NSCLC patients in Malaysia. This Malaysian consensus statement was developed by a panel of experts, chaired by a pathologist and composed of three other pathologists, four respiratory physicians and three oncologists. It reflects currently available scientific data and adaptations of recommendations from international guidelines to the local landscape. Expert recommendations on different aspects of molecular testing agreed upon by the panel are provided as structured discussions. These recommendations address the appropriate patients and samples to be tested, as well as when and how these tests should be performed. The algorithms for molecular testing in metastatic NSCLC, in the first line setting and upon disease progression beyond first line therapy, were developed.

An Oncogenic Role for Four-Jointed Box 1 (FJX1) in Nasopharyngeal Carcinoma.

Nasopharyngeal carcinoma (NPC) is a highly metastatic cancer prevalent in Southern China and Southeast Asia. The current knowledge on the molecular pathogenesis of NPC is still inadequate to improve disease management. Using gene expression microarrays, we have identified the four-jointed box 1 (FJX1) gene to be upregulated in primary NPC tissues relative to nonmalignant tissues. An orthologue of human FJX1, the four-jointed (fj) gene in Drosophila and Fjx1 in mouse, has reported to be associated with cancer progression pathways. However, the exact function of FJX1 in human is not well characterized. The overexpression of FJX1 mRNA was validated in primary NPC tissue samples, and the level of FJX1 protein was significantly higher in a subset of NPC tissues (42%) compared to the normal epithelium, where no expression of FJX1 was observed (p = 0.01). FJX1 is also found to be overexpressed in microarray datasets and TCGA datasets of other cancers including head and neck cancer, colorectal, and ovarian cancer. Both siRNA knockdown and overexpression experiments in NPC cell lines showed that FJX1 promotes cell proliferation, anchorage-dependent growth, and cellular invasion. Cyclin D1 and E1 mRNA levels were increased following FJX1 expression indicating that FJX1 enhances proliferation by regulating key proteins governing the cell cycle. Our data suggest that the overexpression of FJX1 contributes to a more aggressive phenotype of NPC cells and further investigations into FJX1 as a potential therapeutic target for NPC are warranted. The evaluation of FJX1 as an immunotherapy target for NPC and other cancers is currently ongoing.

Erratum: Publisher Correction: Homologous recombination DNA repair defects in PALB2-associated breast cancers.

[This corrects the article DOI: 10.1038/s41523-019-0115-9.].

Homologous recombination DNA repair defects in PALB2-associated breast cancers.

Mono-allelic germline pathogenic variants in the Partner And Localizer of BRCA2 (PALB2) gene predispose to a high-risk of breast cancer development, consistent with the role of PALB2 in homologous recombination (HR) DNA repair. Here, we sought to define the repertoire of somatic genetic alterations in PALB2-associated breast cancers (BCs), and whether PALB2-associated BCs display bi-allelic inactivation of PALB2 and/or genomic features of HR-deficiency (HRD). Twenty-four breast cancer patients with pathogenic PALB2 germline mutations were analyzed by whole-exome sequencing (WES, n = 16) or targeted capture massively parallel sequencing (410 cancer genes, n = 8). Somatic genetic alterations, loss of heterozygosity (LOH) of the PALB2 wild-type allele, large-scale state transitions (LSTs) and mutational signatures were defined. PALB2-associated BCs were found to be heterogeneous at the genetic level, with PIK3CA (29%), PALB2 (21%), TP53 (21%), and NOTCH3 (17%) being the genes most frequently affected by somatic mutations. Bi-allelic PALB2 inactivation was found in 16 of the 24 cases (67%), either through LOH (n = 11) or second somatic mutations (n = 5) of the wild-type allele. High LST scores were found in all 12 PALB2-associated BCs with bi-allelic PALB2 inactivation sequenced by WES, of which eight displayed the HRD-related mutational signature 3. In addition, bi-allelic inactivation of PALB2 was significantly associated with high LST scores. Our findings suggest that the identification of bi-allelic PALB2 inactivation in PALB2-associated BCs is required for the personalization of HR-directed therapies, such as platinum salts and/or PARP inhibitors, as the vast majority of PALB2-associated BCs without PALB2 bi-allelic inactivation lack genomic features of HRD.

Prevalence of HER2 Positivity and Its Clinicopathological Correlation in Locally Advanced/Metastatic Gastric Cancer Patients in Malaysia.

PURPOSE: Human epidermal growth factor receptor 2 (Erbb2/HER2) overexpression, which was previously detected in invasive breast cancer, has now been implicated in advanced gastric cancer (GC) and gastroesophageal junction cancer (GEC). A study was conducted to determine the rate of HER2 positivity in patients with locally advanced or metastatic GC and GEC in Malaysia and to assess the impact of various demographic and clinical parameters on HER2 positivity. METHODS: A total of 228 adult patients with GC or GEC were enrolled from Subang Jaya Medical Centre, Malaysia, for retrospective (210) and prospective study. All patients were subjected to the HER2 immunohistochemistry test using an FDA-approved, standardized test kit. Carcinomas scoring 2+ on immunohistochemistry were further tested with HER2 in situ hybridization (ISH) using an FDA-approved test kit. RESULTS: The overall rate of HER2 positivity in the population studied was 24.6% (n = 56). The rate was significantly higher in men than in women (29.6 vs. 16.3%; p = 0.024). HER2 overexpression was significantly more common in diffuse type than in intestinal type of tumors (39.8 vs. 14.9%; p < 0.001). In our study, out of 56 samples, 44 (78.6%) were considered for gene amplification testing, out of which 40 (90.1%) samples showed gene amplification. There was no statistically significant correlation between HER2 positivity and patient age, race, tumor location, tumor differentiation, and TNM staging. CONCLUSIONS: HER2 overexpression was evident in nearly 25% of the Malaysian patients with locally advanced or metastatic gastric cancer. The overexpression correlated significantly with male gender and diffuse-type tumors. The majority of the IHC-positive tumors demonstrated c-erb2 gene amplification and this finding reached statistical significance.

Epithelial-to-mesenchymal transition (EMT) causing acquired resistance to afatinib in a patient with epidermal growth factor receptor (EGFR)-mutant lung adenocarcinoma.

We report the first case of epithelial-to-mesenchymal transition (EMT) as the cause of acquired resistance to the second-generation EGFR-tyrosine kinase inhibitor (TKI), afatinib in a patient with advanced non-small cell lung cancer (NSCLC) harboring a sensitizing EGFR mutation. Patients with EGFR-mutant NSCLC inevitably develop acquired resistance while on EGFR-TKI treatment. EMT which renders cancer cells more invasive and migratory is one of the mechanisms of acquired resistance to EGFR-TKIs and correlates with a poor prognosis. Possible therapeutic strategies in patients with EMT include blocking M2 muscarinic receptor signalling, targeting EMT with histone deacetylase inhibitors such as entinostat and MEK-inhibitors such as selumetinib, inhibition of microRNAs, immunotherapy and inhibiting fibroblast growth factor receptor-1.