DSpace Repository :: Browsing by Author "Roa, Iván"

Browsing by Author "Roa, Iván"

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Colesterolosis y cáncer de la vesícula biliar
(2010) Roa, Iván; IBACACHE, GILDA; DE ARETXABALA U, XABIER; MUÑOZ N, SERGIO
Cholesterolosis is frequently observed in cholecystectomies performed for lithiasis or chronic cholecystitis. Aim: To determine the degree of association between cholesterolosis and gallbladder cancer. Material and Methods: In a prospective study of gallbladder cancer, all gallbladders obtained during cholecystectomies were processed for pathological study, following a special protocol. As part of this study, 23304 surgical samples obtained between 1993 and 2002 were studied, looking for a relationship between cholesterolosis and chronic cholecystitis, adenomas, dysplasia and gallbladder cancer. Results: Seventy nine percent of patients were women. Cholesterolosis was observed in 3,123 cases (13.4%). Cholesterolosis was more common in women (14.2%) than in men (10.2%) (p < 0.001). In the same period, 29 patients were diagnosed with adenomas (0.12%), 179 cases with dysplasia not associated with gallbladder cancer (0.8%) and 739 gallbladder cancer (3.2%). The frequency of cholesterolosis was 13.8% in chronic cholecystitis, 13.7% in adenomas, 12.1% in dysplasias and 1.35% in patients with gallbladder cancer (p < 0.01). Of the thirteen cases with gallbladder cancer and cholesterolosis, 10 were early gallbladder carcinomas. Patients with cholesterolosis were 9.2 times less likely to have cancer than those who did not have cholesterolosis. Conclusions: Cholesterolosis has a strong negative association with gallbladder cancer.
ERCC1 (Excision repair cross-complementing 1) expression in pT2 gallbladder cancer is a prognostic factor
(2011) Roa, Iván; De Aretxabala, Xabier; Lantadilla, Soledad; Muñoz, Sergio
Gallbladder cancer (GBC) is the main cause of death by malignant tumour in women in Chile. There is no information regarding the role of excision repair cross-complementing group 1 (ERCC1) in GBC. Our aim is to determine the expression and significance of ERCC1 as a prognostic factor in GBC. Tissue microarrays were prepared using 200 surgically resected GBCs and 50 non-malignant gallbladders as controls. In 190 cases, ERCC1 was determined by immunohistochemistry. The correlation between ERCC1 expression and GBC pathological characteristics and patient survival were analysed. Ninety-five percent of the non-malignant gallbladder epithelia showed intense and diffuse ERCC1 expression. GBC cases showed ERCC1 expression in the tumour cells in 100/190 (53%) cases. The best differentiated tumours showed significantly greater expression than the less differentiated (p<0.05). Patients with ERCC1-positive status with subserosal carcinomas (pT2) had significantly better survival than ERCC1-negative patients at 20 and 60 months of follow-up (p=0.005), and the probability of dying was 6 times lower for ERCC1-positive than for ERCC1-negative patients. Our preliminary results show that cholecystectomised patients with GBC in stage pT2 and with ERCC1 expression have significantly better survival than patients at the same stage that did not present ERCC1 expression.
¿Es posible utilizar las muestras de colecistectomías con cáncer en investigación?: Calidad del ADN de muestras obtenidas del sistema público y privado de salud
(Sociedad Médica de Santiago, 2013) Roa, Iván; De Toro, Gonzalo; Sánchez, Tamara; Slater, Jeannie; Ziegler, Anne Marie; Game, Anakaren; Arellano, Leonardo; Schalper, Kurt; De Aretxabala, Xabier
Background: The quality of the archival samples stored at pathology services could be a limiting factor for molecular biology studies. Aim: To determine the quality of DNA extracted from gallbladder cancer samples at different institutions. Material and Methods: One hundred ninety four samples coming from five medical centers in Chile, were analyzed. DNA extraction was quantified determining genomic DNA concentration. The integrity of DNA was determined by polymerase chain reaction amplification of different length fragments of a constitutive gene (β-globin products of 110, 268 and 501 base pairs). Results: The mean DNA concentration obtained in 194 gallbladder cancer samples was 48 ± 43.1 ng/µl. In 22% of samples, no amplification was achieved despite obtaining a mean DNA concentration of 58.3 ng/ul. In 81, 67 and 22% of samples, a DNA amplification of at least 110, 268 or 501 base pairs was obtained, respectively. No differences in DNA concentration according to the source of the samples were demonstrated. However, there were marked differences in DNA integrity among participating centers. Samples from public hospitals were of lower quality than those from private clinics. Conclusions: Despite some limitations, in 80% of cases, the integrity of DNA in archival samples from pathology services in our country would allow the use of molecular biology techniques.
Expresión y amplificación del gen HER2 en el cáncer gástrico avanzado
(Sociedad Médica de Santiago, 2013) Roa, Iván; Slatter, Jeannie; Carvajal, Daniel; Schalper, Kurt; De Toro, Gonzalo; Ares, Raúl; Game, Anakaren; León, Jorge; De Aretxabala, Xabier
Background: Overexpression/amplification of the HER2 gene in advanced gastric cancer is a predictor of response to adjuvant therapy with monoclonal antibodies. Aim: To determine the frequency of HER2 gene overexpression and amplification in advanced gastric cancer. Material and Methods: One hundred nine advanced gastric cancer biopsy specimens, from 76 men and 33 women aged 67 ± 14 and 62 ± 12 years respectively, were selected. Three histological patterns (diffuse, intestinal and mixed) were recognized. Automated immunohistochemistry was performed with monoclonal c-erbB-2 (NCL-356) Novocastra. Fluorescent in situ hybridization (FISH) for HER2 was performed in positive cases. Results: In 39% of cases, immunohistochemical staining was negative. It was 1+, 2+ and 3+ positive in 15, 36 and 11% of cases, respectively. It was positive in 16% and 3% of intestinal type and mixed carcinomas, respectively. It was negative in all diffuse carcinomas. FISH was performed in 39 (2 +) cases and in 11 (3 +) cases. The gene amplification was positive in two (2 +) and 11 (3 +) cases (11.9%). The overall concordance between immunohistochemical staining and in situ hybridization was 85%. Conclusions: In advanced gastric cancer, HER2 gene overexpression or amplification was observed in 11% and 12% of cases, respectively.
Expression of teneurins is associated with tumor differentiation and patient survival in ovarian cancer
(PLoS, 2017) Graumann, Rebecca; Di Capua, Gabriella A.; Oyarzún, Juan; Vásquez, Marcos A.; Liao, Christine; Brañes, Jorge A.; Roa, Iván; Casanello, Paola; Corvalán, Alejandro H.; Owen, Gareth; Delgado, Iris; Uwe, Zangemeister-Wittke; Ziegler, Annemarie
Teneurins are a family of highly conserved pair-rule proteins involved in morphogenesis and development of the central nervous system. Their function in adult tissues and in disease is largely unknown. Recent evidence suggests a role for dysregulated expression of Teneurins in human tumors, but systematic investigations are missing. Here, we investigated Teneurin-2 and Teneurin-4 expression in various cancer cell lines and in ovarian tumor tissues. Teneurin-2 and Teneurin-4 were expressed in most of the breast cancer cell lines tested. Teneurin-4 was also detected in ovarian cancer cell lines, and throughout ovarian tumors and normal ovary tissue. Ovarian tumors with low Teneurin-4 expression showed less differentiated phenotypes and these patients had shorter mean overall survival. Similarly, Teneurin-2 expression correlated with overall survival as well, especially in patients with serous tumors. In the various cell lines, 5-Aza-cytidine-induced changes in DNA methylation did not alter expression of Teneurin-2 and Teneurin-4, despite the existence of predicted CpG islands in both genes. Interestingly, however, we found evidence for the control of Teneurin-2 expression by the oncogenic growth factor FGF8. Furthermore, we identified multiple transcript splicing variants for Teneurin-2 and Teneurin-4, indicating complex gene expression patterns in malignant cells. Finally, downregulation of Teneurin-4 expression using siRNA caused a cell-type dependent increase in proliferation and resistance to cisplatin. Altogether, our data suggest that low Teneurin-4 expression provides a growth advantage to cancer cells and marks an undifferentiated state characterized by increased drug resistance and clinical aggressiveness. We conclude that Teneurin-2 and Teneurin-4 expression levels could be of prognostic value in ovarian cancer.
Inactivation of tumor suppressor gene pten in early and advanced gallbladder cancer
(Biomed Central Ltd., 2015) Roa, Iván; De Toro, Gonzalo; Fernández, Fernanda; Game, Anakaren; Muñoz, Sergio; De Aretxabala, Xabier; Javle, Milind
BACKGROUND: PTEN is a tumor suppressor gene that regulates the PTEN/PI3k/AKT/mTOR pathway, which is frequently altered in human cancers including gallbladder cancer (GBC). To determine the frequency of PTEN expression in GBC and to establish its relation to clinical and morphological parameters and survival in GBC. METHODS: The immunohistochemical expression of PTEN was studied in 108 GBC. All the cases included areas of non-tumor mucosa adjacent to the tumor. RESULTS: The group was comprised of 108 patients, 91 women (84.3%) and 17 men (15.7%) with an average age of 65.2 years (SD ± 12.3 years). Thirty-five cases (33%) were early carcinomas (EC) and the remaining 73 (67%) were advanced cases (AC). All the internal controls were positive (moderate or intense in 96.3%). Only in three AC (4.1%) was there a complete absence of PTEN immunohistochemical expression. There were no significant differences in relation between PTEN expression and tumor infiltration or degree of differentiation. The three patients with PTEN inactivation died before 10 months; however, the other patients with AC had a survival of 53% at 10 months. DISCUSSION: Loss of PTEN expression was observed in 4.1% of the advanced GBC. All the patients with this alteration died before 10 months. PTEN inactivation could be a rare event, but with a poor prognosis in advanced GBC.
Mutación del gen BRAF en pacientes con cánceres de colon y recto con KRAS no mutado
(Sociedad Médica de Santiago, 2014) Roa, Iván; Game, Anakaren; Bizama, Carolina; Schalper, Kurt
Background: In colorectal cancer, BRAF and KRAS mutation are mutually exclusive, but both are independent prognostic factors for the disease. Aim: To determine the frequency of BRAF V600E mutation in colorectal cancer. Material and Methods: A KRAS mutation study was carried out in 100 tissue samples of primary and metastatic adenocarcinomas of colon and rectum from patients aged 61.1 ± 62 years (56 women). Negative KRAS mutation cases underwent study of BRAF V600E mutation by restriction fragment length polymorphism (RFLP) and direct sequencing. Results: Primary tumors were located in the colon and rectum in 88 and six cases respectively. Five were liver metastases and in one case, the sample location was undetermined. Forty two samples were KRAS positive (mutated). In 12 of the 58 KRAS negative (wild type) samples, the V600E mutation in codon 15 of the BRAF gene was demonstrated. No differences in the frequency and distribution of mutations, stratified by gender, age, primary tumor versus metastasis, or tumor location were observed. Conclusions: Twelve percent of KRAS negative colorectal cancer samples showed BRAF gene mutation. Considering that 42% of samples have a KRAS mutation, 54% of patients should not respond to therapies with monoclonal antibodies directed against epidermic growth factor (EGFR) pathway.
Somatic Mutations of PI3K in Early and Advanced Gallbladder Cancer: Additional Options for an Orphan Cancer
(American Society for Investigative Pathology and the Association for Molecular Pathology by Elsevier, 2016) Roa, Iván; Gracía, Hernán; Game, Anakaren; De Toro, Gonzalo; De Aretxabala, Xabier; Javle, Milind
Gallbladder cancer (GBC) is the second-leading cause of death from malignant tumors in Chilean women. The phosphatidylinositol 3-kinase (PI3K) pathway is involved in proliferation, cell survival, and growth. We investigated mutations in exons 9 and 20 of the PI3K gene in GBC. Mutations in exons 9 (E542K, E545G, E545K) and 20 (H1047L and H1047R) of PI3K were determined by direct sequencing in 130 cases of GBC. The patient group consisted of 110 women and 20 men, and mutations were found in 22 cases (16.9%). Of these, 14 cases had mutations in exon 9 (63.6%) (E542K, 64%; E545K, 29%; and E545G, 7%) and 8 in exon 20 (37.4%; H1047L, 50%; H1047R, 50%). No differences were noted in the frequency and type of mutations analyzed by sex, age, or histologic features. We observed mutations in 22% of the early-stage GBC and 14.6% of the advanced cases. In this series of GBC, 17% of cases were noted as having mutations in either exons 9 or 20 of PI3K. These results suggest that therapeutic testing of inhibitors of the PI3K/AKT pathway may be of benefit in advanced GBC patients
Teneurin protein family: An emerging role in human tumorigenesis and drug resistance
(2012) Ziegler, Annemarie; Corvalán, Alejandro; Roa, Iván; Brañes, Jorge; Wollscheid, Bernd
Using a chemoproteomic strategy, we recently demonstrated the expression of teneurin-2, a transmem-brane glycoprotein, in the majority of malignant mesothelioma cell lines. This finding was unexpected since no formally organized evidence existed to implicate teneurins in human malignancy. For this reason, here we provide a comprehensive review on the expression of teneurins in human tumors and cell lines. Current evidence supports the aberrant expression of teneurins in various tumor types, their involvement in cancer-related regulatory networks, and their potential participation in drug resistance. Structural attributes of teneurins could enable the detection of shedded forms in body fluids for clinical applications.

Browsing by Author "Roa, Iván"

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