Biomedical subjects

Edurne Arriola

Publications and source records attributed to Edurne Arriola.

4 recordsLinked to original sources

PubMed2007

Evaluation of Phi29-based whole-genome amplification for microarray-based comparative genomic hybridisation.

For the optimal performance of high throughput genomic technologies sufficient yields of high-quality DNA are crucial. Following microdissection, most samples fail to produce sufficient quantities of DNA for genome-wide experiments. Various PCR-based amplification methods have been used, but these usually produce nonuniform representations of the genome. Bacteriophage Phi29 DNA polymerase random-primed DNA amplification is based on isothermal multiple displacement amplification. We sought to define the genome representation of this method in a bacterial artificial chromosome microarray comparative genomic hybridisation (aCGH) platform. Test genomic female DNA was amplified using Phi29 amplification at four different starting concentrations (0.5, 5, 10 and 50 ng). These products were combined with unamplified and amplified genomic female DNA as reference. In addition, 50 ng of DNA from five microdissected breast cancer frozen samples, were amplified using the same method. Three combinations were performed: unamplified test with unamplified reference, amplified test with unamplified reference and both amplified tumour and reference DNA. aCGH was performed with an in-house 16 K BAC platform (a resolution of approximately 100 Kb). Pearson's correlation tests and hierarchical clustering were performed to compare the profiles obtained. aCGH profiles obtained with amplified test and unamplified reference female genomic DNA showed copy number biases throughout the genome. These biases were more conspicuous with smaller amounts of starting material and mapped to regions of known copy number polymorphisms. When similar concentrations of test and reference DNA were amplified, the biases were significantly reduced, rendering accurate profiles. For the tumours, representative profiles were obtained when both test and reference DNA were amplified. Phi29 amplification induces copy number biases and unamplified material remains the gold standard for copy number analysis. For accurate results using Phi29 amplification, samples subjected to aCGH analysis should be combined with reference DNA amplified with the same method, using similar amounts of starting template.

Breast Neoplasms↗

PubMed2006

MYC amplification in breast cancer: a chromogenic in situ hybridisation study.

AIMS: To analyse the correlation between MYC amplification and various clinicopathological features and outcome in a cohort of 245 patients with invasive breast carcinoma treated with surgery followed by anthracycline-based chemotherapy. Given the high prevalence of MYC amplification in tumours of BRCA1 mutation carriers and the similarities between these and sporadic "basal-like" carcinomas, the prevalence of MYC amplification in "basal-like" breast carcinomas was investigated. METHODS: MYC gene copy number was assessed on tissue microarrays containing duplicate cores of 245 invasive breast carcinomas by means of chromogenic in situ hybridisation using SpotLight C-MYC amplification probe and chromosome 8 centromeric probe (CEP8). Signals were evaluated at 400x magnification; 30 morphologically unequivocal neoplastic cells in each core were counted for the presence of the gene and CEP8 probes. RESULTS: Amplification was defined as a MYC:CEP8 ratio >2. Signals for both MYC and CEP8 were assessable in 196/245 (80%) tumours. MYC amplification was found in 19/196 cases (9.7%) and was not associated with tumour size, histological grade, positivity for oestrogen receptor, progesterone receptor, HER2, epidermal growth factor, cytokeratins 14, 5/6 and 17, MIB1 or p53. Only 4% of basal-like carcinomas showed MYC amplification, compared to 8.75% and 10.7% of luminal and HER2 tumours respectively. On univariate analysis, MYC amplification displayed a significant association with shorter metastasis-free and overall survival and proved to be an independent prognostic factor on multivariate survival analysis. CONCLUSION: MYC amplification is not associated with "basal-like" phenotype and proved to be an independent prognostic factor for breast cancer patients treated with anthracycline-based chemotherapy.

Anthracyclines↗

PubMed2006

Predictive value of HER-2 and Topoisomerase IIalpha in response to primary doxorubicin in breast cancer.

AIM: To study the predictive role of HER-2 and Topoisomerase IIalpha (TOP2A) in response to primary doxorubicin. METHODS: Two hundred and thirty-two patients with operable breast cancer were treated with doxorubicin prior to surgery. ER, PgR, grade, Ki-67 and HER-2 status were prospectively assessed. HER-2 overexpression was evaluated with immunohistochemistry; positive cases were then studied for gene copy number of HER-2, TOP2A and chromosome 17 centromere by chromogenic in situ hybridisation. Clinical response was assessed by mammography. Pathological response was evaluated as the percentage of tumour replaced by changes due to chemotherapy. RESULTS: HER-2 amplification was associated with clinical response (p=0.04). ER and PgR negativity, high Ki-67 and HER-2 amplification significantly correlated to pathological response (p<0.05). Tumours with coamplification of HER-2 and TOP2A showed a higher percentage of pathological changes (p=0.6). However, in the multivariate analysis for complete pathological response, ER negativity and high Ki-67 index were the only parameters that maintained statistical significance. CONCLUSION: HER2 and Topoisomerase IIalpha amplification failed to show an association with pathological response to doxorubicin, whereas ER negativity and a high proliferation rate were predictive of complete pathological response to this regime.

Antibiotics, Antineoplastic↗

PubMed2006

Imaging techniques contribute to increased surgical rescue of relapse in the follow-up of colorectal cancer.

PURPOSE: This study analyzes the results of a follow-up policy in colorectal cancer at our institution and evaluates the possible benefit provided by each test performed. PATIENTS AND METHODS: Six hundred nineteen patients who had radical surgery and adjuvant treatment for colorectal cancer were followed up with a protocol that included carcinoembryonic antigen testing and clinical examination every three months for the first two years, every four months in the third year, and every six months in the fourth and fifth years. Chest X-ray and colonoscopy were performed yearly for five years and abdominal ultrasound was done every six months for the first three years and yearly afterward. Abdominopelvic computerized tomography was performed yearly for the first two years in cases with rectal cancer. If relapse was detected, all operable cases underwent surgery if possible. RESULTS: Between 1993 and 1999, 619 patients were followed-up. Mean follow-up was 66.9 months. Two hundred eight relapses were detected, 83.6 percent in the first three years and 73 (35.1 percent) underwent surgical resection. Carcinoembryonic antigen testing detected 44.2 percent of recurrences and 31.9 percent of them were operated on. Imaging techniques detected a lower percentage of recurrences (18.7 percent) but were more often resectable: 52 percent and 60 percent of the recurrences detected by computerized tomography and chest X-ray, respectively, underwent surgery. Median overall survival of patients with resected relapse was 62 months, significantly higher than those who were not operable (12.4 months). CONCLUSION: Imaging techniques in the surveillance of resected colorectal cancer contribute to early detection of relapse with a high proportion of operable metastatic disease.

Adult↗