Integrative analysis of mRNA and miRNA expression profiles and somatic variants in oxysterol signaling in early-stage luminal breast cancer.

Oxysterols, oxidized derivatives of cholesterol, act in breast cancer (BC) as selective estrogen receptor modulators and affect cholesterol homeostasis, drug transport, nuclear and cell receptors, and other signaling proteins. Using data from three highly overlapping sets of patients (N = 162 in total) with early-stage estrogen-receptor-positive luminal BC-high-coverage targeted DNA sequencing (113 genes), mRNA sequencing, and full micro-RNA (miRNA) transcriptome microarrays-we describe complex oxysterol-related interaction (correlation) networks, with validation in public datasets (n = 538) and 11 databases. The ESR1-CH25H-INSIG1-ABCA9 axis was the most prominent, interconnected through miR-125b-5p, miR-99a-5p, miR-100-5p, miR-143-3p, miR-199b-5p, miR-376a-3p, and miR-376c-3p. Mutations in SC5D, CYP46A1, and its functionally linked gene set were associated with multiple differentially expressed oxysterol-related genes. STARD5 was upregulated in patients with positive lymph node status. High expression of hsa-miR-19b-3p was weakly associated with poor survival. This is the first study of oxysterol-related genes in BC that combines DNA, mRNA, and miRNA multiomics with detailed clinical data. Future studies should provide links between intratumoral oxysterol signaling depicted here, circulating oxysterol levels, and therapy outcomes, enabling eventual clinical exploitation of present findings.

Single Nucleotide Variants in KIF14 Gene May Have Prognostic Value in Breast Cancer.

INTRODUCTION: Human kinesin 14 (KIF14) is one of the 70 prognostic marker genes (so-called Amsterdam profile) previously identified by the microarray of breast carcinomas, and its high transcript expression in tumor specimens indicates a poor prognosis for patients. We performed a pilot study to explore the prognostic and predictive meaning of KIF14 germline genetic variability in breast cancer patients. METHODS: KIF14 coding sequence, including 5' and 3' untranslated regions and overlaps to introns for identification of splicing sites, was analyzed using next-generation sequencing in the testing set of blood DNA samples from 105 breast cancer patients with clinical follow-up. After rigorous evaluation of major allele frequency, haplotype blocks, in silico predicted functional aspects, expression quantitative trait loci, and clinical associations, eight single nucleotide variants were subsequently validated in the evaluation set of 808 patients. RESULTS: Carriers of minor alleles G (rs17448931) or T (rs3806362) had significantly shorter overall survival than wild type homozygotes (p = 0.010 and p = 0.023, respectively) thus successfully replicating the results of the testing set. Both associations remained significant in the multivariate Cox regression analysis, including molecular subtype and stage as covariates (hazard ratio, HR = 1.7, 95% confidence interval (CI) = 1.1-2.8 for rs17448931 and HR = 1.9, CI 1.2-3.0 for rs3806362). DISCUSSION: In conclusion, our preliminary data suggest that minor alleles in rs17448931 and rs3806362 of KIF14 represent candidate biomarkers of poor prognosis of breast cancer patients. After pending validation in independent populations and eventual functional characterization, these candidates might become useful biomarkers in the clinics.

Plasma lipidomic profiles of kidney, breast and prostate cancer patients differ from healthy controls.

Early detection of cancer is one of the unmet needs in clinical medicine. Peripheral blood analysis is a preferred method for efficient population screening, because blood collection is well embedded in clinical practice and minimally invasive for patients. Lipids are important biomolecules, and variations in lipid concentrations can reflect pathological disorders. Lipidomic profiling of human plasma by the coupling of ultrahigh-performance supercritical fluid chromatography and mass spectrometry is investigated with the aim to distinguish patients with breast, kidney, and prostate cancers from healthy controls. The mean sensitivity, specificity, and accuracy of the lipid profiling approach were 85%, 95%, and 92% for kidney cancer; 91%, 97%, and 94% for breast cancer; and 87%, 95%, and 92% for prostate cancer. No association of statistical models with tumor stage is observed. The statistically most significant lipid species for the differentiation of cancer types studied are CE 16:0, Cer 42:1, LPC 18:2, PC 36:2, PC 36:3, SM 32:1, and SM 41:1 These seven lipids represent a potential biomarker panel for kidney, breast, and prostate cancer screening, but a further verification step in a prospective study has to be performed to verify clinical utility.

Hybrid esophagectomy for oesophageal cancer: long-term results. A single-centre experience.

INTRODUCTION: The authors report long-term outcomes in patients who received neoadjuvant chemoradiotherapy and consequently underwent hybrid oesophagectomy for oesophageal cancer (OC). AIM: To evaluate long-term outcomes in patients suffering from OC, who underwent hybrid oesophagectomy. MATERIAL AND METHODS: Our cohort consisted of patients suffering from OC, who received neoadjuvant chemoradiotherapy. Hybrid esophagectomy was performed 8-10 weeks after oncological treatment. RESULTS: Ninety-four patients underwent surgery for OC from 2011 to 2015. Histology revealed adenocarcinoma in 60.6%, squamous cell carcinoma (SCC) in 36.2%, and other type of cancer in 3.2%. Seventy-three (77.7%) patients with advanced stage (T3-4, N0-2, M0) were indicated to receive neoadjuvant chemoradiotherapy (nCRT). Trans-hiatal hybrid oesophagectomy was performed in 83 (88.3%) patients. Transthoracic hybrid oesophagectomy was performed in 11 (11.7%) patients. Histology of the resected specimens of 18 (24.7%) patients did not reveal OC, i.e. pathological complete response (pCR). In our cohort, we proved an association between occurrence of pCR and age as well as disease-free survival (DFS). The patients who presented with pCR were significantly younger - below 60 years of age (p = 0.017). They also showed significantly higher mean DFS (p = 0.004). CONCLUSIONS: Combined oesophagectomy with neoadjuvant chemoradiotherapy results in a better long-term outcome in patients suffering from oesophageal cancer. In our set of patients who underwent hybrid esophagectomy, satisfactory short-term and especially long-term results of surgical treatment for oesophageal cancer were observed.

Role of Genetic Variation in Cytochromes P450 in Breast Cancer Prognosis and Therapy Response.

Breast cancer is the most frequent cancer in the female population worldwide. The role of germline genetic variability in cytochromes P450 (CYP) in breast cancer prognosis and individualized therapy awaits detailed elucidation. In the present study, we used the next-generation sequencing to assess associations of germline variants in the coding and regulatory sequences of all human CYP genes with response of the patients to the neoadjuvant cytotoxic chemotherapy and disease-free survival (n = 105). A total of 22 prioritized variants associating with a response or survival in the above evaluation phase were then analyzed by allelic discrimination in the large confirmation set (n = 802). Associations of variants in CYP1B1, CYP4F12, CYP4X1, and TBXAS1 with the response to the neoadjuvant cytotoxic chemotherapy were replicated by the confirmation phase. However, just association of variant rs17102977 in CYP4X1 passed the correction for multiple testing and can be considered clinically and statistically validated. Replicated associations for variants in CYP4X1, CYP24A1, and CYP26B1 with disease-free survival of all patients or patients stratified to subgroups according to therapy type have not passed a false discovery rate test. Although statistically not confirmed by the present study, the role of CYP genes in breast cancer prognosis should not be ruled out. In conclusion, the present study brings replicated association of variant rs17102977 in CYP4X1 with the response of patients to the neoadjuvant cytotoxic chemotherapy and warrants further research of genetic variation CYPs in breast cancer.

SLC46A1 Haplotype with Predicted Functional Impact has Prognostic Value in Breast Carcinoma.

BACKGROUND AND OBJECTIVE: Membrane solute carrier transporters play an important role in the transport of a wide spectrum of substrates including anticancer drugs and cancer-related physiological substrates. This study aimed to assess the prognostic relevance of gene expression and genetic variability of selected solute carrier transporters in breast cancer. METHODS: Gene expression was determined by quantitative real-time polymerase chain reaction. All SLC46A1 and SLCO1A2 exons and surrounding non-coding sequences in DNA extracted from the blood of patients with breast cancer (exploratory phase) were analyzed by next-generation sequencing technology. Common variants (minor allele frequency ≥ 5%) with in silico-predicted functional relevance were further analyzed in a large cohort of patients with breast cancer (n = 815) and their prognostic and predictive potential was estimated (validation phase). RESULTS: A gene expression and bioinformatics analysis suggested SLC46A1 and SLCO1A2 to play a putative role in the prognosis of patients with breast cancer. In total, 135 genetic variants (20 novel) were identified in both genes in the exploratory phase. Of these variants, 130 were non-coding, three missense, and two synonymous. One common variant in SLCO1A2 and four variants in SLC46A1 were predicted to be pathogenic by in silico programs and subsequently validated. A SLC46A1 haplotype block composed of rs2239911-rs2239910-rs8079943 was significantly associated with ERBB2/HER2 status and disease-free survival of hormonally treated patients. CONCLUSIONS: This study revealed the prognostic value of a SLC46A1 haplotype block for breast cancer that should be further studied.

Role of Genetic Variation in ABC Transporters in Breast Cancer Prognosis and Therapy Response.

Breast cancer is the most common cancer in women in the world. The role of germline genetic variability in ATP-binding cassette (ABC) transporters in cancer chemoresistance and prognosis still needs to be elucidated. We used next-generation sequencing to assess associations of germline variants in coding and regulatory sequences of all human ABC genes with response of the patients to the neoadjuvant cytotoxic chemotherapy and disease-free survival (n = 105). A total of 43 prioritized variants associating with response or survival in the above testing phase were then analyzed by allelic discrimination in the large validation set (n = 802). Variants in ABCA4, ABCA9, ABCA12, ABCB5, ABCC5, ABCC8, ABCC11, and ABCD4 associated with response and variants in ABCA7, ABCA13, ABCC4, and ABCG8 with survival of the patients. No association passed a false discovery rate test, however, the rs17822931 (Gly180Arg) in ABCC11, associating with response, and the synonymous rs17548783 in ABCA13 (survival) have a strong support in the literature and are, thus, interesting for further research. Although replicated associations have not reached robust statistical significance, the role of ABC transporters in breast cancer should not be ruled out. Future research and careful validation of findings will be essential for assessment of genetic variation which was not in the focus of this study, e.g., non-coding sequences, copy numbers, and structural variations together with somatic mutations.

Lipidomic characterization of exosomes isolated from human plasma using various mass spectrometry techniques.

Ultrahigh-performance supercritical fluid chromatography - mass spectrometry (UHPSFC/MS), ultrahigh-performance liquid chromatography - mass spectrometry (UHPLC/MS), and matrix-assisted laser desorption/ionization (MALDI) - MS techniques were used for the lipidomic characterization of exosomes isolated from human plasma. The high-throughput methods UHPSFC/MS and UHPLC/MS using a silica-based column containing sub-2 µm particles enabled the lipid class separation and the quantitation based on exogenous class internal standards in <7 minute run time. MALDI provided the complementary information on anionic lipid classes, such as sulfatides. The nontargeted analysis of 12 healthy volunteers was performed, and absolute molar concentration of 244 lipids in exosomes and 191 lipids in plasma belonging to 10 lipid classes were quantified. The statistical evaluation of data included principal component analysis, orthogonal partial least square discriminant analysis, S-plots, p-values, T-values, fold changes, false discovery rate, box plots, and correlation plots, which resulted in the information on lipid changes in exosomes in comparison to plasma. The major changes were detected in the composition of triacylglycerols, diacylglycerols, phosphatidylcholines, and lysophosphatidylcholines, whereby sphingomyelins, phosphatidylinositols, and sulfatides showed rather similar profiles in both biological matrices.

Complications of the surgical treatment of esophageal cancer and microbiological analysis of the respiratory tract.

AIM: The aim of this study was to reduce the severe respiratory complications of esophageal cancer surgery often leading to death. METHODS: Two groups of patients operated on for esophageal cancer were evaluated in this retrospective analysis. The first group was operated between 2006-2011, prior to the implementation of preoperative microbiological examination while the second group had surgery between 2012-2017 after implementation of this examination. RESULTS: In total, 260 patients, 220 males and 40 females underwent esophagectomy. Between 2006-2011, 113 (87.6%) males and 16 (12.4%) females and between 2012-2017, esophagectomy was performed in 107 (81.7%) males and 24 (18.3%) females. In the first cohort, 10 patients died due to respiratory complications. The 30-day mortality was 6.9% and 90-day was 9.3%. In the second cohort, 4 patients died from respiratory complications. The 30-day mortality was 1.5% and 90-day mortality was 3.1%. With regard to the incidence of respiratory complications (P=0.014), these occurred more frequently in patients with sputum collection, however, severe respiratory complications were more often observed in patients without sputum collection. Significantly fewer patients died (P=0.036) in the group with sputum collection. The incidence of respiratory complications was very significantly higher in the patients who died (P<0.0001). CONCLUSION: The incidence of severe respiratory complications (causing death) may be reduced by identifying clinically silent respiratory tract infections.

Respiratory complications following mini-invasive laparoscopic and thoracoscopic esophagectomy for esophageal cancer. Experience in 215 patients.

INTRODUCTION: Respiratory complications (RC) including respiratory failure and adult respiratory distress syndrome (ARDS) affect the outcomes of esophagectomy substantially. In order to decrease their incidence, identification of important features of RC is necessary. AIM: To evaluate the incidence and risk factors of postoperative RC following hybrid esophagectomy. MATERIAL AND METHODS: The retrospective analysis of consecutive hybrid esophagectomies for malignancies (transhiatal laparoscopic or thoracoscopic resection and limited open reconstruction phase) assessed the incidence and outcomes of RC in relation to the patients' age, ASA score, neoadjuvant therapy, type of surgical procedure, TNM stage, the incidence of anastomotic leak and Clavien-Dindo classification. RESULTS: Transhiatal laparoscopic (176, 81.9%) or thoracoscopic hybrid esophagectomy (39, 18.1%, conversion in 7 patients) was completed in 215 patients, 187 (87%) men and 28 (13%) women. Respiratory complications developed in 86 (40%) and severe respiratory failure or ARDS occurred in 29 (13.5%) patients. The overall in-hospital mortality was 7.4%, 30-day mortality 5.6% (RC 9, myocardial infarction 1, conduit necrosis 1), and 90-day mortality a further 1.8% (multiple organ failure, ARDS). The incidence of RC correlates significantly with ASA score II and III (p = 0.0002) and Clavien-Dindo grade 4 and 5 in severe RC (p < 0.0001). Furthermore, hospital stay (p < 0.0001) and mortality (p < 0.0001) were significantly increased in RC. CONCLUSIONS: The results show a higher occurrence of RC in polymorbid patients and patients with severe complications according to the Clavien-Dindo classification. Adequate risk management including surgical technique and perioperative prophylaxis and therapy of RC should be studied and standardized.

Reversed phase UHPLC/ESI-MS determination of oxylipins in human plasma: a case study of female breast cancer.

The ultrahigh-performance liquid chromatography-mass spectrometry (UHPLC/MS) method was optimized and validated for the determination of oxylipins in human plasma using the targeted approach with selected reaction monitoring (SRM) in the negative-ion electrospray ionization (ESI) mode. Reversed phase UHPLC separation on an octadecylsilica column enabled the analysis of 63 oxylipins including numerous isomeric species within 12-min run time. The method was validated (calibration curve, linearity, limit of detection, limit of quantification, carry-over, precision, accuracy, recovery rate, and matrix effect) and applied to 40 human female plasma samples from breast cancer patients and age-matched healthy volunteers (control). Thirty-six oxylipins were detected in human plasma with concentrations above the limit of detection, and 21 of them were quantified with concentrations above the limit of quantitation. The concentrations determined in healthy controls are in a good agreement with previously reported data on human plasma. Quantitative data were statistically evaluated by multivariate data analysis (MDA) methods including principal component analysis (PCA) and orthogonal partial least square discriminant analysis (OPLS-DA). S-plot and box plots showed that 13-HODE, 9-HODE, 13-HOTrE, 9-HOTrE, and 12-HHTrE were the most upregulated oxylipin species in plasma of breast cancer patients.

Chronic Inflammation as a Potential Predictive Factor of Nivolumab Therapy in Non-small Cell Lung Cancer.

AIM: To investigate potential associations between clinical and standard peripheral blood biomarkers and clinical outcome in patients with non-small cell lung cancer (NSCLC) treated with nivolumab. PATIENTS AND METHODS: A total of 120 patients with advanced NSCLC treated at seven comprehensive cancer care centers were analyzed in this national retrospective study. Survival statistics were evaluated using the Kaplan-Meier method and Cox analysis. RESULTS: Among clinical parameters, histology was significantly associated with progression-free survival. Univariate Cox-proportional hazards model indicated prognostic and predictive role of a panel of laboratory parameters reflecting chronic inflammatory pattern (elevated neutrophil count, neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, C-reactive protein and decrease in hemoglobin and albumin). Higher serum calcium concentration was also associated with nivolumab treatment effect. CONCLUSION: Tumor histology was the only clinical parameter predicting the outcome of nivolumab treatment. Among the laboratory parameters, our analysis identified a laboratory panel reflecting chronic inflammation as a potential predictive marker of nivolumab treatment.

Use of Germline Genetic Variability for Prediction of Chemoresistance and Prognosis of Breast Cancer Patients.

The aim of our study was to set up a panel for targeted sequencing of chemoresistance genes and the main transcription factors driving their expression and to evaluate their predictive and prognostic value in breast cancer patients. Coding and regulatory regions of 509 genes, selected from PharmGKB and Phenopedia, were sequenced using massive parallel sequencing in blood DNA from 105 breast cancer patients in the testing phase. In total, 18,245 variants were identified of which 2565 were novel variants (without rs number in dbSNP build 150) in the testing phase. Variants with major allele frequency over 0.05 were further prioritized for validation phase based on a newly developed decision tree. Using emerging in silico tools and pharmacogenomic databases for functional predictions and associations with response to cytotoxic therapy or disease-free survival of patients, 55 putative variants were identified and used for validation in 805 patients with clinical follow up using KASPTM technology. In conclusion, associations of rs2227291, rs2293194, and rs4376673 (located in ATP7A, KCNAB1, and DFFB genes, respectively) with response to neoadjuvant cytotoxic therapy and rs1801160 in DPYD with disease-free survival of patients treated with cytotoxic drugs were validated and should be further functionally characterized.

From Tumor Immunology to Immunotherapy in Gastric and Esophageal Cancer.

Esophageal and gastric cancers represent tumors with poor prognosis. Unfortunately, radiotherapy, chemotherapy, and targeted therapy have made only limited progress in recent years in improving the generally disappointing outcome. Immunotherapy with checkpoint inhibitors is a novel treatment approach that quickly entered clinical practice in malignant melanoma and renal cell cancer, but the role in esophageal and gastric cancer is still poorly defined. The principal prognostic/predictive biomarkers for immunotherapy efficacy currently considered are PD-L1 expression along with defects in mismatch repair genes resulting in microsatellite instability (MSI-H) phenotype. The new molecular classification of gastric cancer also takes these factors into consideration. Available reports regarding PD-1, PD-L1, PD-L2 expression and MSI status in gastric and esophageal cancer are reviewed to summarize the clinical prognostic and predictive role together with potential clinical implications. The most important recently published clinical trials evaluating checkpoint inhibitor efficacy in these tumors are also summarized.

HILIC/ESI-MS determination of gangliosides and other polar lipid classes in renal cell carcinoma and surrounding normal tissues.

Negative-ion hydrophilic liquid chromatography-electrospray ionization mass spectrometry (HILIC/ESI-MS) method has been optimized for the quantitative analysis of ganglioside (GM3) and other polar lipid classes, such as sulfohexosylceramides (SulfoHexCer), sulfodihexosylceramides (SulfoHex2Cer), phosphatidylglycerols (PG), phosphatidylinositols (PI), lysophosphatidylinositols (LPI), and phosphatidylserines (PS). The method is fully validated for the quantitation of the studied lipids in kidney normal and tumor tissues of renal cell carcinoma (RCC) patients based on the lipid class separation and the coelution of lipid class internal standard with the species from the same lipid class. The raw data are semi-automatically processed using our software LipidQuant and statistically evaluated using multivariate data analysis (MDA) methods, which allows the complete differentiation of both groups with 100% specificity and sensitivity. In total, 21 GM3, 28 SulfoHexCer, 26 SulfoHex2Cer, 10 PG, 19 PI, 4 LPI, and 7 PS are determined in the aqueous phase of lipidomic extracts from kidney tumor tissue samples and surrounding normal tissue samples of 20 RCC patients. S-plots allow the identification of most upregulated (PI 40:5, PI 40:4, GM3 34:1, and GM3 42:2) and most downregulated (PI 32:0, PI 34:0, PS 36:4, and LPI 16:0) lipids, which are primarily responsible for the differentiation of tumor and normal groups. Another confirmation of most dysregulated lipids is performed by the calculation of fold changes together with T and p values to highlight their statistical significance. The comparison of HILIC/ESI-MS data and matrix-assisted laser desorption/ionization mass spectrometric imaging (MALDI-MSI) data confirms that lipid dysregulation patterns are similar for both methods. Graphical abstract ᅟ.

Immunotherapy in mucosal melanoma: a case report and review of the literature.

BACKGROUND: Mucosal melanoma is a rare form of melanoma presenting variably as sores or unexplained bleeding located mainly in the head and neck region, anorectal region or female genital tract. Mucosal melanoma is usually diagnosed at an advanced stage and is characterized by an aggressive behavior. Surgery represents the mainstay of treatment for early stage melanomas, but for advanced disease there have been until recently very limited treatment options. Ipilimumab, a human monoclonal antibody directed against the cytotoxic T lymphocyte antigen 4, was the first treatment modality to demonstrate survival benefit in advanced malignant melanoma. METHOD: Description of a new case and review of the literature. RESULTS: We present here a patient with mucosal melanoma with aggressive biological behavior and documented late response to ipilimumab. CONCLUSIONS: Ipilimumab represents an effective treatment option in selected patients with mucosal melanoma.

MiR-301a-3p Suppresses Estrogen Signaling by Directly Inhibiting ESR1 in ERα Positive Breast Cancer.

BACKGROUND/AIMS: MiRNA-301a-3p is an oncogenic miRNA whose expression is associated with tumor development, metastases and overall poor prognosis. Estrogen receptor α (ERα) is one of the estrogen hormone-activated transcription factors, which regulates a large number of genes and is involved in the mammary gland development. Expression of ERα is considered to be a good indicator for endocrine therapy and breast cancer survival. Loss of ERα in breast cancer patients indicates invasiveness and poor prognosis. In this study, we focus on the regulation of ERα by miR-301a and its role in transition from estrogen-dependent to estrogen-independent breast cancer. METHODS: Expression of miR-301a-3p was measured by qRT-PCR in tumor tissue samples from 111 patients with primary breast carcinoma and in mammospheres representing in vitro model of cancer stem-like cells. Dual reporter luciferase assay and complementary experiments were performed to validate ESR1 as a direct target of miR-301a-3p. The effect of miR-301a-3p on estrogen signaling was evaluated on the level of gene and protein expression and growth response to estrogens. Finally, the effect of miR-301a-3p expression on tumor growth was studied in nude mice. RESULTS: We identified ESR1 as a direct target of miR-301a-3p. Ectopic miR-301a-3p causes a decrease in ESR1 mRNA and protein level and modulates the expression of ERα target genes in ERα positive breast cancer cells. Consistently, miR-301a-3p causes a decrease in sensitivity of MCF7 cells to 17ß-estradiol and inhibits the growth of estrogen dependent tumor in nude mice. Yet, the mice tumors have significantly increased expression of genes related to cancer stem-like cells and epithelial to mesenchymal transition suggesting enrichment of the population of cells with more invasive properties, in line with our observation that miR-301a-3p expression is highly increased in mammospheres which show a decrease in estrogenic signaling. Importantly, miR-301a-3P level is also increased in primary breast cancer samples exhibiting an ER/PR negative phenotype. CONCLUSION: Our results confirm ESR1 as a direct target of miR-301a-3p and suggest that miR-301a-3p likely contributes to development of estrogen independence, which leads to a more invasive phenotype of breast cancer.

ABC Transporters and Their Role in the Neoadjuvant Treatment of Esophageal Cancer.

The prognosis of esophageal cancer (EC) is poor, despite considerable effort of both experimental scientists and clinicians. The tri-modality treatment consisting of neoadjuvant chemoradiation followed by surgery has remained the gold standard over decades, unfortunately, without significant progress in recent years. Suitable prognostic factors indicating which patients will benefit from this tri-modality treatment are missing. Some patients rapidly progress on the neoadjuvant chemoradiotherapy, which is thus useless and sometimes even harmful. At the same time, other patients achieve complete remission on neoadjuvant chemoradiotherapy and subsequent surgery may increase their risk of morbidity and mortality. The prognosis of patients ranges from excellent to extremely poor. Considering these differences, the role of drug metabolizing enzymes and transporters, among other factors, in the EC response to chemotherapy may be more important compared, for example, with pancreatic cancer where all patients progress on chemotherapy regardless of the treatment or disease stage. This review surveys published literature describing the potential role of ATP-binding cassette transporters, the genetic polymorphisms, epigenetic regulations, and phenotypic changes in the prognosis and therapy of EC. The review provides knowledge base for further research of potential predictive biomarkers that will allow the stratification of patients into defined groups for optimal therapeutic outcome.

Stereotactic radiotherapy in the treatment of local recurrences of esophageal cancer.

Esophageal cancer (EC) consists of tumors with a generally poor prognosis, and treatment options for patients with disease recurrence are extremely limited. Due to this poor patient prognosis, the possible treatment toxicity should be carefully balanced against its potential benefit and patient quality of life. Stereotactic body radiotherapy (SBRT) is a rapidly expanding novel technique combining a short treatment time together with high local efficacy and an acceptable toxicity profile. There are no publications thus far presenting data regarding the usage of SBRT utilizing a conventional linear accelerator in locally recurrent EC patients. In the present study, 2 patients with recurrent EC in the neck lymph nodes were treated by SBRT in the Department of Oncology, University Hospital Olomouc, Czech Republic. The treatment dose was 30 and 40 Gy in 5 daily fractions, with a prescribed dose to 65 and 81% isodose, for each patient respectively, utilizing a volumetric arc therapy technique, a 6-MV photon beam and an Elekta Synergy linear accelerator. The treatment was delivered without any unintentional treatment interruptions and without any treatment-related acute toxicity. The maximum dose in the patients was 45.9 and 49.2 Gy, respectively. The maximum doses for the surrounding major blood vessels were 35.4 and 45.7 Gy, respectively. Maximum doses to the trachea and the esophagus in the first patient were 32.6 and 27.0 Gy. In the second patient, these doses were not clinically significant. SBRT utilizing linear accelerators should be considered in patients with localized recurrent EC, offering the patients the chance for local control with minimal treatment toxicity.