HER2 testing in gastric cancer: An update Lucas Faria Abrahao-Machado Cristovam Scapulatempo-Neto
World journal of gastroenterology : WJG,
05/2016, Volume:
22, Issue:
19
Journal Article
Open access
Human epidermal growth factor receptor 2(HER2) overexpression is increasingly recognized as a frequent molecular abnormality in gastric and gastroesophageal cancer. With the recent introduction of ...HER2 molecular targeted therapy for patients with advanced gastric cancer, determination of HER2 status is crucial in order to select patients who may benefit from this treatment. This paper provides an update on our knowledge of HER2 in gastric and gastroesophageal cancer, including the prognostic relevance of HER2, the key differences between HER2 protein expression interpretation in breast and gastric cancer, the detection methods and the immunohistochemistry scoring system.
Biosensors for early detection of cancer biomarkers normally depend on specific interactions between such biomarkers and immobilized biomolecules in the sensing units. Though these interactions are ...expected to yield specific, irreversible adsorption, the underlying mechanism appears not to have been studied in detail. In this paper, we show that adsorption explained with the Langmuir-Freundlich model is responsible for detection of the antigen p53 associated with various types of cancers. Irreversible adsorption was proven between anti-p53 antibodies immobilized on the biosensors and the antigen p53, with the adequacy of the Langmuir-Freundlich model being confirmed with three independent experimental methods,
viz.
polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS), nanogravimetry using a quartz crystal microbalance and electrochemical impedance spectroscopy. The method based on this irreversible adsorption was sufficiently sensitive (limit of detection of 1.4 pg mL
−1
) for early diagnosis of Hodgkin lymphoma, pancreatic and colon carcinomas, and bladder, ovarian and lung cancers, and could distinguish between MCF7 cells containing the antigen p53 from Saos-2 cells that do not contain it.
The Langmuir-Freundlich model is used to explain the adsorption of the p53 biomarker onto an immunosensor for early detection of cancer.
Next generation sequencing technology has greatly reduced the cost and time required for sequencing a genome. An approach that is rapidly being adopted as an alternative method for CNV analysis is ...the low-pass whole genome sequencing (LP-WGS). Here, we evaluated the performance of LP-WGS to detect copy number variants (CNVs) in clinical cytogenetics.
DNA samples with known CNVs detected by chromosomal microarray analyses (CMA) were selected for comparison and used as positive controls; our panel included 44 DNA samples (12 prenatal and 32 postnatal), comprising a total of 55 chromosome imbalances. The selected cases were chosen to provide a wide range of clinically relevant CNVs, the vast majority being associated with intellectual disability or recognizable syndromes. The chromosome imbalances ranged in size from 75 kb to 90.3 Mb, including aneuploidies and two cases of mosaicism.
All CNVs were successfully detected by LP-WGS, showing a high level of consistency and robust performance of the sequencing method. Notably, the size of chromosome imbalances detected by CMA and LP-WGS were compatible between the two different platforms, which indicates that the resolution and sensitivity of the LP-WGS approach are at least similar to those provided by CMA.
Our data show the potential use of LP-WGS to detect CNVs in clinical diagnosis and confirm the method as an alternative for chromosome imbalances detection. The diagnostic effectiveness and feasibility of LP-WGS, in this technical validation study, were evidenced by a clinically representative dataset of CNVs that allowed a systematic assessment of the detection power and the accuracy of the sequencing approach. Further, since the software used in this study is commercially available, the method can easily be tested and implemented in a routine diagnostic setting.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Background
Oropharyngeal squamous cell carcinomas (OpSCCs) are commonly associated with high rates of treatment failure.
Objectives
To evaluate methylation‐based markers in plasma from OpSCC patients ...as emerging tools for accurate/noninvasive follow‐up.
Methods
Pretreatment formalin‐fixed paraffin‐embedded (FFPE) biopsies (n = 52) and paired plasma (n = 15) were tested for the methylation of CCNA1, DAPK, CDH8, and TIMP3 by droplet digital PCR (ddPCR).
Results
Seventy‐one percent (37/52) of the biopsies showed methylation of at least one of the evaluated genes and tumor CCNA1 methylation was associated with recurrence‐free survival. Methylated circulating tumor DNA (meth‐ctDNA) was detected in 11/15 (73.3%) plasma samples; conversely, plasma samples from healthy controls were all negative for DNA methylation (area under the curve = 0.867; 95% confidence interval = 0.720‐1.000). Additionally, preliminary results on the detection of meth‐ctDNA in plasma collected during follow‐up closely matched patient outcome.
Conclusions
The results suggest the feasibility of detecting meth‐ctDNA in plasma using ddPCR and a possible application on routine setting after further validation.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
In this pilot study, we aimed to evaluate the feasibility of whole genome sequencing (WGS) as a first‐tier diagnostic test for infants hospitalized in neonatal intensive care units in the Brazilian ...healthcare system. The cohort presented here results from a joint collaboration between private and public hospitals in Brazil considering the initiative of a clinical laboratory to provide timely diagnosis for critically ill infants. We performed trio (proband and parents) WGS in 21 infants suspected of a genetic disease with an urgent need for diagnosis to guide medical care. Overall, the primary indication for genetic testing was dysmorphic syndromes (n = 14, 67%) followed by inborn errors of metabolism (n = 6, 29%) and skeletal dysplasias (n = 1, 5%). The diagnostic yield in our cohort was 57% (12/21) based on cases that received a definitive or likely definitive diagnostic result from WGS analysis. A total of 16 pathogenic/likely pathogenic variants and 10 variants of unknown significance were detected, and in most cases inherited from an unaffected parent. In addition, the reported variants were of different types, but mainly missense (58%) and associated with autosomal diseases (19/26); only three were associated with X‐linked diseases, detected in hemizygosity in the proband an inherited from an unaffected mother. Notably, we identified 10 novel variants, absent from public genomic databases, in our cohort. Considering the entire diagnostic process, the average turnaround time from enrollment to medical report in our study was 53 days. Our findings demonstrate the remarkable utility of WGS as a diagnostic tool, elevating the potential of transformative impact since it outperforms conventional genetic tests. Here, we address the main challenges associated with implementing WGS in the medical care system in Brazil, as well as discuss the potential benefits and limitations of WGS as a diagnostic tool in the neonatal care setting.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Esophageal cancer is an aggressive tumor that has a high rate of incidence and mortality worldwide. It is the 10th most frequent type in Brazil, being squamous cell carcinoma (ESCC) the predominant ...subtype. There is currently an incessant search to identify the frequently altered genes associated with esophageal squamous cell carcinoma biology that could be druggable. This study aimed to analyze the somatic mutation profile of a large panel of cancer-related genes in Brazilian ESCC. In a series of 46 ESCC diagnoses at Barretos Cancer Hospital, DNA isolated from paired fresh-frozen and blood tissue, a panel of 150 cancer-related genes was analyzed by next-generation sequencing. The genes with the highest frequency of mutations were TP53 (39/46, 84.8%), followed by NOTCH1 (7/46, 15.2%), NFE2L2 (5/46, 10.8%), RB1 (3/46, 6.5%), PTEN (3/46, 6.5%), CDKN2A (3/46, 6.5%), PTCH1 (2/46, 4.3%) and PIK3CA (2/46, 4.3%). There was no significant association between molecular and patients' clinicopathological features. Applying an evolutionary action score of p53 (EAp53), we observed that 14 (35.9%) TP53 mutations were classified as high-risk, yet no association with overall survival was observed. Concluding, this the largest mutation profile of Brazilian ESCC patients, which helps in the elucidation of the major cancer-related genes in this population.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Background
Some studies reported that differential gene expression could be used as a biomarker for high‐grade cervical lesion identification. The aim was to evaluate the gene expression profile of ...cervical intraepithelial neoplasia (CIN) to identify a gene expression signature of CIN2+ in liquid‐based cytology (LBC) samples.
Methods
LBC samples (n = 85) obtained from women who underwent colposcopy were included with benign (n = 13), CIN1 (n = 26), CIN2 (n = 16), and CIN3 (n = 30) diagnoses. After RNA isolation, gene expression profiling was performed using the nCounter PanCancer Pathways, which consists of 730 cancer‐related genes. The genes identified were in silico expression evaluated using the UALCAN database. An accurate prediction model to discriminate CIN2+ from <CIN2 lesions was determined. Immunohistochemistry was performed to assess the expression of p16 and Ki67 proteins.
Results
This study identified a gene expression profile that significantly differentiates CIN2+ cases from <CIN2. The gene signature comprised 18 genes, two genes downregulated and 16 upregulated. In silico analysis corroborated the differential expression of 11 of those genes. Further observed was that high expression of BMP7 (odds ratio OR, 4.202), CDKN2C (OR, 5.326), HIST1H3G (OR, 3.522), PKMYT1 (OR, 4.247), and menarche age (OR, 1.608) were age‐adjusted and associated with CIN2+. This model demonstrates a probability of 43% leading to an area under the curve (of .979; sensitivity of 94.9%, and specificity of 91.2% for CIN2+ prediction. It was observed that p16 expression was significantly associated with CDKN2A mRNA overexpression (p = .0015).
Conclusion
A gene expression profile that may be helpful in the identification of patients with CIN2+ was identified. This approach could be used together with currently used LBC in a clinical setting, allowing the identification of patients with high risk of CIN2+.
A gene expression profile of cancer‐related genes was performed by nCounter in liquid‐based cytology of cervical intraepithelial neoplasia lesions. Using molecular and clinical data, an accurate model was created to discriminate CIN2+ lesions from <CIN2.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Regional lymph nodes are affected frequently by melanoma metastasis. Its microenvironment may be associated with tumor progression. We investigated sentinel nodes with and without tumor and negative ...nodes surrounding positive nodes, looking for patterns related to tumor immune interaction and lymphovascular progression. We quantified programmed cell death protein 1 (PD-1)/programmed cell death-ligand 1, vascular endothelial growth factor (VEGF)-A/VEGF-C expressions in lymph nodes of 103 patients who underwent sentinel lymph node biopsy. Two groups were studied: negative sentinel lymph nodes and positive ones. Negative lymph nodes of sequential lymphadenectomy from positive cases were also studied. Markers were assessed by immunohistochemistry. Results were related to clinical/histological outcomes. VEGF-A/VEGF-C analysis showed higher positivity in metastatic nodes and higher positivity in the surrounding negative nodes from positive cases in comparison with nonmetastatic patients. Programmed cell death-ligand 1, studied only in metastasis, presented high positivity, not associated with prognosis. PD-1 expressions were similar in the groups with a 1% cutoff and higher in the metastasis with a 5% cutoff. Higher VEGF-A expression was related to higher pathological stages. PD-1 expression in the lymph node was associated with higher survival. Other clinical and histopatological variables were not associated with marker expression patterns. VEGF-A and VEGF-C expressions in lymph nodes were associated with the presence of lymph node metastasis. PD-1 expression in the lymph node was related to higher survival rates and this should be explored in the context of adjuvant immunotherapy.
Lung cancer is the deadliest cancer worldwide. The mutational frequency of EGFR and KRAS genes in lung adenocarcinoma varies worldwide per ethnicity and smoking. The impact of EGFR and KRAS mutations ...in Brazilian lung cancer remains poorly explored. Thus, we investigated the frequency of EGFR and KRAS mutations in a large Brazilian series of lung adenocarcinoma together with patients' genetic ancestry, clinicopathological and sociodemographic characteristics. The mutational frequency of EGFR was 22.7% and KRAS was 20.4%. The average ancestry proportions were 73.1% for EUR, 13.1% for AFR, 6.5% for AME and 7.3% for ASN. EGFR mutations were independently associated with never-smokers, high-Asian ancestry, and better performance status. KRAS mutations were independently associated with tobacco exposure and non-Asian ancestry. EGFR-exon 20 mutations were associated with worse outcome. The Cox regression model indicated a worse outcome for patients whose were older at diagnosis (>61 y), solid histological subtype, loss of weight (>10%), worse performance status (≥2), and presence of KRAS mutations and EGFR mutational status in TKi non-treated patients. In conclusion, we assessed the clinicopathological and ethnic impact of EGFR and KRAS mutations in the largest series reported of Brazilian lung adenocarcinomas. These findings can support future clinical strategies for Brazilian lung cancer patients.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Ependymomas (EPN) are central nervous system neoplasms that exhibit an ependymal phenotype. In particular, supratentorial EPN (ST‐EPN) must be differentiated from more aggressive entities such as ...glioblastoma, IDH‐wildtype. This task is frequently addressed with the use of immunohistochemistry coupled with clinical presentation and morphological features. Here we describe the case of a young adult presenting with migraine‐like symptoms and a temporoinsular‐based expansile mass that was first diagnosed as a GBM, mostly based on strong and diffuse oligodendrocyte transcription factor 2 (OLIG2) expression. Molecular characterization revealed a ZFTA::RELA fusion, supporting the diagnosis of ST‐EPN, ZFTA fusion‐positive. OLIG2 expression is rarely reported in tumors other than GBM and oligodendrocyte‐lineage committed neoplasms. The patient was treated with radiotherapy and temozolomide after surgery and was alive and well at follow‐up. This report illustrates the need to assess immunostains within a broader clinical, morphological and molecular context to avoid premature exclusion of important differential diagnoses.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
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