María Pardo

A strategy to reveal potential glycan markers from serum glycoproteins associated with breast cancer progression

Aberrant glycosylation on glycoproteins that are either presented on the surface or secreted by cancer cells is a potential source of disease biomarkers and provides insights into disease pathogenesis. N-Glycans of the total serum glycoproteins from advanced breast cancer patients and healthy individuals were sequenced by HPLC with fluorescence detection coupled with exoglycosidase digestions and mass spectrometry. We observed a significant increase in a trisialylated triantennary glycan containing alpha1,3-linked fucose which forms part of the sialyl Lewis x epitope. Following digestion of the total glycan pool with a combination of sialidase and beta-galactosidase, we segregated and quantified a digestion product, a monogalactosylated triantennary structure containing alpha1,3-linked fucose. We compared breast cancer patients and controls and detected a 2-fold increase in this glycan marker in patients. In 10 patients monitored longitudinally, we showed a positive correlation between this glycan marker and disease progression and also demonstrated its potential as a better indicator of metastasis compared to the currently used biomarkers, CA 15-3 and carcinoembryonic antigen (CEA). A pilot glycoproteomic study of advanced breast cancer serum highlighted acute-phase proteins alpha1-acid glycoprotein, alpha1-antichymotrypsin, and haptoglobin beta-chain as contributors to the increase in the glycan marker which, when quantified from each of these proteins, marked the onset of metastasis in advance of the CA 15-3 marker. These preliminary findings suggest that specific glycans and glycoforms of proteins may be candidates for improved markers in the monitoring of breast cancer progression.

Gastric cancer occurrence in preneoplastic lesions: A long-term follow-up in a high-risk area in Spain

There are no established criteria to classify patients into high or low risk of progressing to gastric cancer (GC). The aim of the study was to identify predictors of GC occurrence among patients with gastric preneoplastic lesions. A prospective and retrospective follow‐up study was carried out in a province in Spain with one of the highest risk of GC. The study included 478 patients who underwent gastric biopsy in 1988–1994 with diagnoses of normal mucosa, nonatrophic gastritis (NAG), non‐metaplastic multifocal atrophic gastritis (MAG) and complete or incomplete intestinal metaplasia (IM) and who accepted to undergo a new biopsy during 2005–2007 or had an event during follow up. Inter‐ and intra‐observer variability of histological diagnosis was assessed. Analysis was done using Cox proportional hazards risk (HR) models. The mean age of the patients was 50 years, 47% were males and the mean follow‐up time was 12.8 years. During follow‐up, 23 GC (4.8%) were diagnosed (21 adenocarcinomas and 2 lymphomas) with an incidence of 3.77 per 1,000 person per year. The incidence rate of GC for those with incomplete IM was 16.5 per 1,000 person years. Out the 21 adenocarcinomas, 16 had an incomplete IM in the baseline diagnosis. Incomplete IM (HR 11.3; 95% CI 3.8–33.9) and a family history of GC (HR 6.1; 95% CI 1.7–22.4) were the strongest risk factors for gastric adenocarcinoma. Subtyping of IM and family history of GC may be useful for the identification of high‐risk patients who need more intensive surveillance.

Abnormal cell cycle regulation in primary human uveal melanoma cultures

Uveal malignant melanoma is the most frequent primary intraocular tumor in adult humans. The cellular events leading to neoplasic transformation of normal uveal melanocytes are not well known when compared to other cancers. In this study, we investigated the role of G1 and G1/S regulatory proteins of the cell cycle in human uveal melanoma (UM) primary cell cultures, since these proteins are common targets in tumor development. Further, freshly established and characterized tumor cells are a better model for in vitro studies when compared to cell lines established long ago. Human primary cell cultures from eight different UM were established, as well as one primary culture from rhesus uveal normal melanocytes (UNM). Primary human UM cultures were characterized by a low establishment and growing rate. From four successful cultures, three showed a high expression of cyclin D1, cyclin E, p16INK4A, and p27KIP1 with no variations in cyclin A, cyclin‐dependent kinase 2 (CDK2), and CDK4. Interestingly, in one of the cultured tumors, tumor suppressor protein retinoblastoma (Rb) did not bind E2F despite the fact that Rb was found in its hypophosphorylated form. No mutations in either RB1 or the Rb‐binding pocket of E2F‐1 were detected. Furthermore, we identified seven proteins co‐immunoprecipitating with Rb in this tumor, including Lamin A/C and six proteins not previously reported to bind Rb: Hsc70, high mobility group protein 1 (HMG‐1), hnRPN, glyceraldehyde 3 phosphate dehydrogenase (G3PDH), EF‐1, and EF‐2. Our results indicate that the overexpression of cyclins D1/E and CDKIs p16 and p27, together with a deregulation of the Rb/E2F pathway, may be implicated in the development of human UM.

Gene expression study and pathway analysis of histological subtypes of intestinal metaplasia that progress to gastric cancer

Background Intestinal metaplasia (IM) is a precursor lesion that precedes gastric cancer (GC). There are two IM histological subtypes, complete (CIM) and incomplete (IIM), the latter having higher progression rates to GC. This study was aimed at analysing gene expression and molecular processes involved in the progression from normal mucosa to IM, and also from IM subtypes to GC. Methodology We used expression data to compare the transcriptome of healthy gastric mucosa to that of IM not progressing to GC, and the transcriptome of IM subtypes that had progressed to GC to those that did not progress. Some deregulated genes were validated and pathway analyses were performed. Results Comparison of IM subtypes that had progressed to GC with those that did not progress showed smaller differences in the expression profiles than the comparison of IM that did not progress with healthy mucosa. New transcripts identified in IM not progressing to GC included TRIM, TMEM, homeobox and transporter genes and SNORD116. Comparison to normal mucosa identified non tumoral Warburg effect and melatonin degradation as previously unreported processes involved in IM. Overexpressed antigen processing is common to both IM-subtypes progressing to GC, but IIM showed more over-expressed oncogenic genes and molecular processes than CIM. Conclusions There are greater differences in gene expression and molecular processes involved in the progression from normal healthy mucosa to IM than from IM to gastric cancer. While antigen processing is common in both IM-subtypes progressing to GC, more oncogenic processes are observed in the progression of IIM.

Correction for Ferreira et al., A Novel Method for Genotyping the Helicobacter pylori vacA Intermediate Region Directly in Gastric Biopsy Specimens

Volume 50, no. 12, p. [3983–3989][1], 2012. Page 3988: The following sentence should be inserted after the first sentence of the Acknowledgments section. “This work was also supported by FEDER funds through Programa Operacional Factores de Competitividade—COMPETE (FCOMP-01-0124-FEDER 021251