Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

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Microarray profiling of rectal tumor samples

ABSTRACT: Using Human WG CodeLink microarrays, we established the expression profiling of 26 LARC without metastasis to gain insight into the molecular signatures associated with response to treatment after CRT. The study initially included a total of 35 consecutive patients with locally advanced rectal cancer (LARC) treated at Virgen de las Nieves Hospital from 2008 until 2010. Written informed consent was obtained from all the patients, and the study protocol was approved by the local Clinical Research (Ethics) Committee. They were distributed in two subgroups following a histological classification of response to treatment. Pretherapeutic staging was performed, including complete medical history and physical evaluation, digital rectal examination, endorectal ultrasound, rigid rectoscopy, colonoscopy, PET/TC and chest x-ray. Tumor samples were prospectively obtained during the rectoscopy. All patients subsequently received a total dose of 50.4Gy of radiatio (28 fractions of 1.8Gy) associated with capecitabine or capecitabine and oxaliplatine. Standardized surgery was performed, including total mesorectal excision, after an interval of 8 weeks after chemoradiotherapy. Tumor response was assessed in surgical specimen by semi-quantitative pathological examination (regression grade) including UICC stage. Histopathological tumor regression was graded based on the semiquantitative 5 point tumor regression grading (TRG) system: TRG1 or a TRG2 scores were considered Responders, whereas TRG3, TRG4, and TRG5 scores were classified as Non-Responders. In addition, the tumor regression or radiotherapy effects were assessed by positron emission tomography (18F-FDG PET). Tumor samples of LARC were collected from 35 patients. Nine patients were finally excluded due to the poor quality of the RNA or contradictory results of MandardM-BM-4s criteria and histopathological downstaging, resulting a total of 26 patients. Complete clinical data regarding, age, sex, stage of disease, response to therapy, and overall survival from 26 patients (10 responders and 16 non-responders) was provided in the sample characteristics field. CRT: Chemoradiation; Cap: Capecitabine; Capox: Capecitabine and Oxaliplatine; cTN: clinical stage; Surg: surgical technique; LAR: Low anterior resection; APR: Abdmino-perineal resection; HART: Hartmann, TRG: Tumor Regression Grade; Downst: Downstaging; Downs: downsizing, Resp: response, CPR: complete pathologic response

ORGANISM(S): Homo sapiens

SUBMITTER: Carlos Cano

PROVIDER: E-GEOD-53781 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:Background: MicroRNAs (miRNAs) are small, non-coding, RNA molecules which regulate numerous cellular processes. Specific miRNA may be abnormally down-regulated or up-regulated in colorectal cancer and have been found associated with prognosis or response to treatments. However, no study has ever addressed their predictive role in rectal cancer. Therefore, we used microarray technology and RT-PCR to profile miRNA expression patterns in patients (pts) with rectal cancer, with the aim to identify a specific M-bM-^@M-^\signatureM-bM-^@M-^] associated with pathological complete response after neoadjuvant chemo-radiotherapy. Methods: 38 pts with locally advanced rectal cancer (cT3-4/N+) were treated with capecitabine-oxaliplatin and pelvic conformal radiotherapy (45 cGy) followed by surgery (after 6-8 weeks). Pathologic response was scored according to the tumor regression grade (TRG) scale. MiRNA expression profile was analysed by microarray on fresh frozen biopsies obtained before treatment start and confirmed by RT-PCR. The correlation between miRNA expression profile and the TRG coded as TRG1 (pathologic Complete Response-pCR) versus TRG >1 (no pCR) was assessed by statistical analysis methods specifically designed for this study. Findings: 14 miRNAs were selected by arrays analysis as differentially expressed in TRG1 pts and 13 were confirmed by RT-PCR. In particular, 11 miRNAs (miR-1183, miR-483-5p, miR-622, miR-125a-3p, miR-1224-5p, miR-188-5p, miR-1471, miR-671-5p, miR-1909*, miR-630 and miR-765) were significantly up-regulated in TRG1 pts, while 2 miRNAs were under -expressed (miR-1274b and miR-720). miR-622 and miR-630 showed 100% sensitivity and specificity in selecting TRG1 cases and were significantly correlated with EGFR (M-OM-^G2=11M-bM-^@M-"793; p= 0M-bM-^@M-"001) and TS expression (M-OM-^G2=10M-bM-^@M-"589; p= 0M-bM-^@M-"001). Interpretation: A set of 13 miRNAs is strongly associated with pathologic complete response and may represent a specific marker of response to chemo-radiotherapy in locally advanced rectal cancer. Experiments were performed on purified RNA from preoperatory biopsies of 38 patients with histological diagnosis of rectal adenocarcinoma invading through the intestinal wall and/or with pelvic lymph node involvement as evaluated by endorectal ultrasonography (uT3-T4 and/or uN+). Patients were treated with neoadjuvant chemo-radiotherapy (capecitabine + oxaliplatin in combination with 45 Gy of pelvic conformal radiotherapy). Patients have been divided in the following two groups: group A those who had obtained a pathologic complete response M-bM-^@M-^S TRG 1, including the patient without detectable disease who refused surgery, group B any pathologic response other than complete.

Project description:Background: Neoadjuvant chemoradiotherapy (NCRT) is the treatment of choice in advanced rectal cancer, even though there are many patients who will not benefit from it. There are still no effective methods for predicting which patients will respond or not. The present study aimed to define the genomic profile of rectal tumors and to identify alterations that are predictive of response in order to optimize therapeutic strategies. Methods: Forty-eight candidates for NCRT were recruited and their pretherapy biopsies analyzed by array Comparative Genomic Hybridization (aCGH). Pathologic response was evaluated by tumor regression grade (TRG).Results: Both Smoothing and Hidden Markov Model (HMM) approaches identified similar alterations, with a prevalence of DNA gains. Non responsive patients had a different alteration profile from responsive ones, with a higher number of genome changes mainly located on 2q21, 7q21, 7q36, 13q12, 13q32-34, 16p13, 17p12 chromosomal regions. Conclusion: This exploratory study suggests that an in depth characterization of chromosomal alterations by aCGH would provide useful predictive information about response to NCRT and help to optimize therapy in rectal cancer patients. 48 samples included in the study were analyzed on whole genome BAC arrays with the aim to characterize genomic alterations and correlate them with the tumor response to therapy. The case series was composed by 15%,81% and 4% of uT2, uT3 and uT4 tumors, respectively. At the diagnosis 56% of patients had uN0 tumors and 44% uN+. 30%,13%, 23% and 34% of patients reached/mantained respectively ypT0, ypT1, ypT2 and ypT3. With regard to response to NCRT, according to TRG criteria proposed by Dworak, two group were defined: non responders (TRG0-2= 56%) and responders (TRG3-4=44%). Clinical and pathological parameters: uT: pre-therapy stage determined by ultrasounds techniques uN: pre-therapy lymph node status determined by ultrasounds techniques ypT: pathologic stage after a neoadjuvant treatment ypN: pathologic lymph node status after a neoadjuvant treatment

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Microarray profiling of rectal tumor samples

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