TP53 mutation profile of esophageal squamous cell carcinomas of patients from Southeastern Brazil

Profile of esophageal squamous cell carcinoma mutations in Brazilian patients

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.

Mutations, Differential Gene Expression, and Chimeric Transcripts in Esophageal Squamous Cell Carcinoma Show High Heterogeneity

Esophageal squamous cell carcinoma (ESCC) is a frequent and lethal neoplasia. As recent advances in targeted therapy have not improved ESCC prognosis, characterization of molecular alterations associated to this tumor is of foremost relevance. In this study, we analyze, for the first time, the complete genomic profile of ESCC by RNA-seq. TP53 was the most frequently mutated gene in the investigation and validation sets (78.6% and 67.4%, respectively). Differential expression analysis between tumor and nontumor adjacent mucosa showed 6698 differentially expressed genes, most of which were overexpressed (74%). Enrichment analysis identified overrepresentation of Wnt pathway, with overexpressed activators and underexpressed inactivators, suggesting activation of canonical and noncanonical Wnt signaling pathways. Higher WNT7B expression was associated with poor prognosis. Twenty-one gene fusions were identified in 50% of tumors, none of which involving the same genes in different patients; 71% of fusions involved syntenic genes. Comparisons with TCGA data showed co-amplification of seven gene pairs involved in fusions in the present study (~33%), suggesting that these rearrangements might have been driven by chromoanagenesis. In conclusion, genomic alterations in ESCC are highly heterogeneous, impacting negatively in target therapy development.

Atorvastatin Downregulates In Vitro Methyl Methanesulfonate and Cyclophosphamide Alkylation-Mediated Cellular and DNA Injuries

Statins are 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, and this class of drugs has been studied as protective agents against DNA damages. Alkylating agents (AAs) are able to induce alkylation in macromolecules, causing DNA damage, as DNA methylation. Our objective was to evaluate atorvastatin (AVA) antimutagenic, cytoprotective, and antigenotoxic potentials against DNA lesions caused by AA. AVA chemopreventive ability was evaluated using antimutagenicity assays (Salmonella/microsome assay), cytotoxicity, cell cycle, and genotoxicity assays in HepG2 cells. The cells were cotreated with AVA and the AA methyl methanesulfonate (MMS) or cyclophosphamide (CPA). Our datum showed that AVA reduces the alkylation-mediated DNA damage in different in vitro experimental models. Cytoprotection of AVA at low doses (0.1–1.0 μM) was observed after 24 h of cotreatment with MMS or CPA at their LC₅₀, causing an increase in HepG2 survival rates. After all, AVA at 10 μM and 25 μM had decreased effect in micronucleus formation in HepG2 cells and restored cell cycle alterations induced by MMS and CPA. This study supports the hypothesis that statins can be chemopreventive agents, acting as antimutagenic, antigenotoxic, and cytoprotective components, specifically against alkylating agents of DNA.

Anti-inflammatory effect of diterpenes-enriched fractions from Pterodon polygalaeflorus through inhibition of macrophage migration and cytokine production

Objectives

To evaluate the anti-inflammatory potential of Pterodon polygalaeflorus hexane extract (HE) and its fractions on macrophage migration in vitro and in vivo.

Methods

Hexane extract from P. polygalaeflorus fruits was fractionated and yielded four fractions. RAW 264.7 cells were treated with samples to evaluate cell viability (MTT assay), cell migration (wound healing and transwell assays), CD14 expression (flow cytometry), iNOS and cytokine mRNA expression (RT-qPCR), NO (Griess reaction) and cytokine (ELISA) production. In vivo migration was evaluated on the thioglycollate-induced peritonitis model. Qualitative analysis was performed by GC-MS.

Key findings

All fractions inhibited the NO production by LPS-stimulated RAW 264.7 cells. Fr3 and Fr4 presented the lowest IC50 values. The expressions of iNOS and IL-1β, TNF-α and IL-10 cytokines were inhibited by Fr3 and Fr4, whereas the CD14 expression was only inhibited by Fr3. All the samples inhibited RAW 264.7 migration in the wound healing and transwell assays. Fr3 and Fr4 reduced the migration of Mac-1+Gr-1− cells to the peritoneum and presented in their compositions: 6α-hydroxy-7β-acetoxyvouacapan-17β-oate, methyl 6α,7β-dihydroxyvouacapan-17β-oate, methyl 6α-acetoxy-7β-hydroxyvouacapan-17β-oate, geranylgeraniol and 14,15-epoxy-geranylgeraniol.

Conclusions

The anti-inflammatory effects of Fr3 and Fr4 involve inhibition of cell migration, iNOS expression and NO production, cytokine expression (mRNA and proteins) and CD14 expression (Fr3).

International cancer seminars: a focus on esophageal squamous cell carcinoma

The International Agency for Research on Cancer (IARC) and the US National Cancer Institute (NCI) have initiated a series of cancer-focused seminars [Scelo G, Hofmann JN, Banks RE et al. International cancer seminars: a focus on kidney cancer. Ann Oncol 2016; 27(8): 1382-1385]. In this, the second seminar, IARC and NCI convened a workshop in order to examine the state of the current science on esophageal squamous cell carcinoma etiology, genetics, early detection, treatment, and palliation, was reviewed to identify the most critical open research questions. The results of these discussions were summarized by formulating a series of 'difficult questions', which should inform and prioritize future research efforts.

Mutational profile of TP53 in esophageal squamous cell carcinoma associated with chagasic megaesophagus

Chaga's disease is an important communicable neglected disease that is gaining wider attention due to its increasing incidence worldwide. Achalasia due to chagasic megaesophagus (CM), a complication of this disease, is a known-yet, poorly understood-etiological factor for esophageal squamous cell carcinoma (ESCC) development. In this study, we aimed to perform the analysis of TP53 mutations in a series of Brazilian patients with ESCC that developed in the context CM (ESCC/CM), and to compare with the TP53 mutation profile of patients with benign CM and patients with nonchagasic ESCC. Additionally, we intended to correlate the TP53 mutation results with patient's clinical pathological features. By polymerase chain reaction (PCR) followed by direct sequencing of the hotspot regions of TP53 (exon 5 to 8), we found that TP53 mutations were present in 40.6% (13/32) of the ESCC/CM group, 45% (18/40) of the nonchagasic ESCC group, and in only 3% (1/33) of the benign CM group. Missense mutations were the most common in the three groups, yet, the type and mutated exon mutation varied significantly among the groups. Clinically, the groups exhibited distinct features, with both cancer groups (ESCC and ESCC/CM) been significantly associated higher consumption of alcohol and tobacco, older age, worse Karnofsky performance status, poor outcome than the patients with benign CM. No significant association was found between TP53 mutation profile and clinical-pathological features in any of the three groups. We describe first the time the analysis of TP53 mutations in ESCC that developed in the context of CM, and the observed high frequency of mutations, suggest that TP53 also plays an important role in the tumorigenic process of this unexplored etiological condition.

Association Between Smoking and p53 Mutation in Oesophageal Squamous Cell Carcinoma: A Meta-analysis

AIMS

Several studies have evaluated the association between smoking and p53 mutation in oesophageal squamous cell carcinoma (ESCC), but the conclusions are inconsistent. The aim of the present study was to carry out a meta-analysis evaluating the relationship between smoking and p53 mutation in patients with ESCC.

MATERIALS AND METHODS

Eligible studies were identified through searches in PubMed and EMBASE. The odds ratio with 95% confidence interval was used to assess the association. In total, 20 studies were identified that met the selection criteria; these studies were analysed using STATA 12.0 software.

RESULTS

The 20 studies identified comprised 1524 ESCC patients, of whom 72.97% were smokers and 27.03% were non-smokers. The pooled odds ratio of p53 mutation in ESCC for any cigarette smoking versus no smoking was 1.28 (95% confidence interval=0.88-1.88). The estimated odds ratios were 1.06 (95% confidence interval=0.56-2.00, based on five studies, 129 light smokers and 70 non-smokers) for light smoking and 2.01 (95% confidence interval=1.12-3.60, based on five studies, 223 heavy smokers and 73 non-smokers) for heavy smoking.

CONCLUSION

The results of our meta-analysis indicate an overall positive relationship between heavy smoking and p53 mutation in ESCC. Heavy smokers with ESCC have a higher risk for p53 mutation than non-smokers. Large-scale clinical studies are still needed to draw a more precise conclusion.

The potential of molecular markers to improve interventions through the natural history of oesophageal squamous cell carcinoma

EC (oesophageal cancer) is one of the ten most frequent and fatal tumours worldwide and ESCC (oesophageal squamous cell carcinoma) accounts for about 80% of the cases. The first symptoms of ESCC arise late during the progression of the disease and, therefore, the diagnosis is usually done in advanced stages. This leads to an inefficient treatment and consequently to a poor prognosis. Thus, a comprehensive knowledge of ESCC biology is of major importance to identify risk factors, especially in high-incidence areas and biomarkers which could enable ESCC prevention and interventions throughout the natural history of the disease. In this review, we present the current knowledge regarding ESCC aetiology as well as the different genetic and epigenetic alterations already described in this tumour. We also discuss how these alterations could be used to anticipate ESCC diagnosis as well as how they can help improving treatment. A molecular natural history of the disease is proposed pointing out potential markers that may improve interventions at different points of ESCC development. Only when the different layers of complexity behind this tumour are elucidated, it will be possible to successfully perform prevention at different levels.

High-throughput genotyping in metastatic esophageal squamous cell carcinoma identifies phosphoinositide-3-kinase and BRAF mutations

Background

Given the high incidence of metastatic esophageal squamous cell carcinoma, especially in Asia, we screened for the presence of somatic mutations using OncoMap platform with the aim of defining subsets of patients who may be potential candidate for targeted therapy.

Methods and Materials

We analyzed 87 tissue specimens obtained from 80 patients who were pathologically confirmed with esophageal squamous cell carcinoma and received 5-fluoropyrimidine/platinum-based chemotherapy. OncoMap 4.0, a mass-spectrometry based assay, was used to interrogate 471 oncogenic mutations in 41 commonly mutated genes. Tumor specimens were prepared from primary cancer sites in 70 patients and from metastatic sites in 17 patients. In order to test the concordance between primary and metastatic sites from the patient for mutations, we analyzed 7 paired (primary-metastatic) specimens. All specimens were formalin-fixed paraffin embedded tissues and tumor content was >70%.

Results

In total, we have detected 20 hotspot mutations out of 80 patients screened. The most frequent mutation was PIK3CA mutation (four E545K, five H1047R and one H1047L) (N = 10, 11.5%) followed by MLH1 V384D (N = 7, 8.0%), TP53 (R306, R175H and R273C) (N = 3, 3.5%), BRAF V600E (N = 1, 1.2%), CTNNB1 D32N (N = 1, 1.2%), and EGFR P733L (N = 1, 1.2%). Distributions of somatic mutations were not different according to anatomic sites of esophageal cancer (cervical/upper, mid, lower). In addition, there was no difference in frequency of mutations between primary-metastasis paired samples.

Conclusions

Our study led to the detection of potentially druggable mutations in esophageal SCC which may guide novel therapies in small subsets of esophageal cancer patients.

HPV infection in Brazilian patients with esophageal squamous cell carcinoma: interpopulational differences, lack of correlation with surrogate markers and clinicopathological parameters

The role of HPV in esophageal squamous cell carcinoma (ESCCs) is controversial. Therefore, we determined, through different methodologies, the prevalence of HPV in 264 ESCC samples from Brazil, and correlated it with the presence of surrogate markers and clinicopathological characteristics. HPV is present in 13% of ESCC, and with a 3-fold variation between high and medium incidence areas. Most HPV positive tumors were infected with HPV16, but this was not associated with p16 expression, TP53 mutation status, patient age, amount of tobacco or alcohol consumption, or overall survival. We conclude that HPV infection may not have a role in ESCC.

Extremely high Tp53 mutation load in esophageal squamous cell carcinoma in Golestan Province, Iran

Background

Golestan Province in northeastern Iran has one of the highest incidences of esophageal squamous cell carcinoma (ESCC) in the world with rates over 50 per 100,000 person-years in both sexes. We have analyzed TP53 mutation patterns in tumors from this high-risk geographic area in search of clues to the mutagenic processes involved in causing ESCC.

Methodology/Principal Findings

Biopsies of 119 confirmed ESCC tumor tissue from subjects enrolled in a case-control study conducted in Golestan Province were analyzed by direct sequencing of TP53 exons 2 through 11. Immunohistochemical staining for p53 was carried out using two monoclonal antibodies, DO7 and 1801. A total of 120 TP53 mutations were detected in 107/119 cases (89.9%), including 11 patients with double or triple mutations. The mutation pattern was heterogeneous with infrequent mutations at common TP53 “hotspots” but frequent transversions potentially attributable to environmental carcinogens forming bulky DNA adducts, including 40% at bases known as site of mutagenesis by polycyclic aromatic hydrocarbons (PAHs). Mutations showed different patterns according to the reported temperature of tea consumption, but no variation was observed in relation to ethnicity, tobacco or opium use, and alcoholic beverage consumption or urban versus rural residence.

Conclusion/Significance

ESCC tumors in people from Golestan Province show the highest rate of TP53 mutations ever reported in any cancer anywhere. The heterogeneous mutation pattern is highly suggestive of a causative role for multiple environmental carcinogens, including PAHs. The temperature and composition of tea may also influence mutagenesis.