Volatilomic profiles of gastric juice in gastric cancer patients.

Volatilomics is a powerful tool capable of providing novel biomarkers for the diagnosis of gastric cancer. The main objective of this study was to characterize the volatilomic signatures of gastric juice in order to identify potential alterations induced by gastric cancer. Gas chromatography with mass spectrometric detection, coupled with headspace solid phase microextraction as the pre-concentration technique, was used to identify volatile organic compounds (VOCs) released by gastric juice samples collected from 78 gastric cancer patients and two cohorts of controls (80 and 96 subjects) from four different locations (Latvia, Ukraine, Brazil, and Colombia). 1440 distinct compounds were identified in samples obtained from patients and 1422 in samples provided by controls. However, only 6% of the VOCs exhibited an incidence higher than 20%. Amongst the volatiles emitted, 18 showed differences in their headspace concentrations above gastric juice of cancer patients and controls. Ten of these (1-propanol, 2,3-butanedione, 2-pentanone, benzeneacetaldehyde, 3-methylbutanal, butylated hydroxytoluene, 2-pentyl-furan, 2-ethylhexanal, 2-methylpropanal and phenol) appeared at significantly higher levels in the headspace of the gastric juice samples obtained from patients; whereas, eight species showed lower abundance in patients than found in controls. Given that the difference in the volatilomic signatures can be explained by cancer-related changes in the activity of certain enzymes or pathways, the former set can be considered potential biomarkers for gastric cancer, which may assist in developing non-invasive breath tests for the diagnosis of this disease. Further studies are required to elucidate further the mechanisms that underlie the changes in the volatilomic profile as a result of gastric cancer.

Evaluation of Bacteria and Fungi DNA Abundance in Human Tissues.

Whereas targeted and shotgun sequencing approaches are both powerful in allowing the study of tissue-associated microbiota, the human: microorganism abundance ratios in tissues of interest will ultimately determine the most suitable sequencing approach. In addition, it is possible that the knowledge of the relative abundance of bacteria and fungi during a treatment course or in pathological conditions can be relevant in many medical conditions. Here, we present a qPCR-targeted approach to determine the absolute and relative amounts of bacteria and fungi and demonstrate their relative DNA abundance in nine different human tissue types for a total of 87 samples. In these tissues, fungi genomes are more abundant in stool and skin samples but have much lower levels in other tissues. Bacteria genomes prevail in stool, skin, oral swabs, saliva, and gastric fluids. These findings were confirmed by shotgun sequencing for stool and gastric fluids. This approach may contribute to a more comprehensive view of the human microbiota in targeted studies for assessing the abundance levels of microorganisms during disease treatment/progression and to indicate the most informative methods for studying microbial composition (shotgun versus targeted sequencing) for various samples types.

Identification of DNA mutations in gastric washes from gastric adenocarcinoma patients: Possible implications for liquid biopsies and patient follow-up.

Whereas cancer patients have benefited from liquid biopsies, the scenario for gastric adenocarcinoma (GAC) is still dismal. We used next-generation deep sequencing of TP53-a highly mutated and informative gene in GAC-to assess mutations in tumor biopsies, plasma (PL) and stomach fluids (gastric wash-GW). We evaluated their potential to reveal tumor-derived mutations, useful for monitoring mutational dynamics at diagnosis, progression and treatment. Exon-capture libraries were constructed from 46 patients including tumor biopsies, GW and PL pre and post-treatment (196 samples), with high vertical coverage >8,000×. At diagnosis, we detected TP53 mutations in 15/46 biopsies (32.6%), 7/46 GW- (15.2%) and 6/46 PL-samples (13%). Biopsies and GW were concordant in 38/46 cases (82.6%) for the presence/absence of mutations and, furthermore, four GW-exclusive mutations were identified, suggesting tumor heterogeneity. Considering the combined analysis of GW and PL, TP53 mutations found in biopsies were also identified in 9/15 (60%) of cases, the highest detection level reported for GAC. Our study indicates that GW could be useful to track DNA alterations, especially if anchored to a comprehensive gene-panel designed for this malignancy.

Genomics and epidemiology for gastric adenocarcinomas (GE4GAC): a Brazilian initiative to study gastric cancer

Gastric cancer (GC) is the fifth most common type of cancer worldwide with high incidences in Asia, Central, and South American countries. This patchy distribution means that GC studies are neglected by large research centers from developed countries. The need for further understanding of this complex disease, including the local importance of epidemiological factors and the rich ancestral admixture found in Brazil, stimulated the implementation of the GE4GAC project. GE4GAC aims to embrace epidemiological, clinical, molecular and microbiological data from Brazilian controls and patients with malignant and pre-malignant gastric disease. In this letter, we summarize the main goals of the project, including subject and sample accrual and current findings

Alternative technique in secondary tracheoesophageal puncture using flexible endoscope and overtube in patients with difficult post-laryngectomy abnormalities

Background: Functional speech rehabilitation after total laryngectomy remains one of the most challenging issues in head and neck multidisciplinary care. Tracheoesophageal puncture for voice prosthesis insertion performed as a secondary procedure with a rigid esophagoscope and trocar can be technically difficult in certain patients due to post-treatment cervical abnormalities, such as reduced hyperextension, stenosis, and trismus. Methods: This study presents an improved method of secondary tracheoesophageal prosthesis insertion using a flexible endoscope in association with a plastic pliable overtube to keep the virtual esophageal lumen open. By this method, the puncture can be performed easily and safely with the avoidance of unexpected lesions. Results: From 2005 to 2015, 12 (16,9%) out of 71 patients who underwent secondary voice prosthesis placement at our institution required this alternative technique due to anatomical alterations that hindered the execution of the procedure following the standard technique. Conclusion: The procedure was successfully performed in all patients with no related complications (AU)

Diagnosis of second primary tumor and long-term survival after single initial triple endoscopy in patients with head and neck cancer.

Patients with squamous cell carcinoma of the upper aerodigestive tract (UADT) have a high risk of developing second primary tumors (SPTs). Most of the studies concerning triple endoscopy (laryngoscopy, digestive tract endoscopy and bronchoscopy) describe the frequency and stage of the SPT, but not its impact on survival. This study is a matched pair analysis that included patients with squamous cell carcinoma of the UADT who were subjected to a triple endoscopy before the first treatment, matched with patients who did not undergo triple endoscopy. One hundred and thirty-five patients were included in each group. The diagnosis of an SPT was more frequent in the initial triple endoscopy group than in the control group (34 and 20 cases, respectively). In the initial triple endoscopy group, 50.0 % of these tumors were diagnosed simultaneously, whereas in the control, only 5.0 %. No significant differences in the survival rates or in clinical stage of the SPTs were found in the two groups. There was no difference in the clinical stage of the SPT and the survival rates of the patient groups who underwent triple endoscopy at the initial evaluation and those subjected to only a routine evaluation and follow-up.