In:
Journal of Clinical Oncology, American Society of Clinical Oncology (ASCO), Vol. 36, No. 4_suppl ( 2018-02-01), p. 700-700
Abstract:
700 Background: The standard of care for locally advanced rectal cancer (RC) is neoadjuvant chemoradiotherapy (CRT) with 5FU aimed to tumor downstaging prior to radical resection but there is a wide spectrum of responses to it, from none to complete. The aim of this project is to validate top candidate genes previously identified by microarray studies as prognostic and predictive classifiers of locally advanced RC, using the NanoString nCounter Platform. Methods: Two cohorts of RC patients were identified according to tumor regression grade (TRG) of AJCC Staging Manual (7th) system: 1) good prognosis: patients that after neoadjuvant CRT obtained TRG0 (complete response); 2) poor prognosis: patients with TRG1 (moderate response), patients with TRG2 (minimum response rate) and patients with TRG3 (poor response). Pre-treatment biopsies tissues from ten TRG0 patients (ID TRG0bio) and thirteen TRG1-3 patients (ID TRG1-3bio) were macro-dissected from FFPE sections, RNA isolated and used for expression profiling of a 305 genes custom code set consisting of 12 normalizer genes, 101 prognostic genes (markers of stemness, invasiveness, proliferation, drug-resistance), 192 predictive genes (involved in response to 5-FU, to radiation therapy and in the response to CRT). All samples were normalized using the geometric mean of the housekeeper genes. P-values were calculated by student’s t-test and was consider significance if was less than 0.05. Gene-specific RNA expression profiles were compared using Spearman's correlation. The heat map was generated using MeV 4.9.0. Results: When we compared TRG0bio to TRG1-3bio tissues, among the 305 genes assayed, changes in expression levels of 18 genes (SSB, GAPDH, TXNDC9, DUT, PKM, STAT1,SLC28A3, DAG1, TYMS, FERMT1, ARNT,SLC6A6, SMAD3, SCRN1, POU5F1, GNG4, PDRG1, ATP5E) were statistically significant. Conclusions: Results suggest that TRG0 RC is characterized by distinct molecular events compared TRG1-3 disease. Next steps will be: to amplify sample size, to understand signaling pathways of top differentially expressed genes and to validate prospectively our gene signature.
Type of Medium:
Online Resource
ISSN:
0732-183X
,
1527-7755
DOI:
10.1200/JCO.2018.36.4_suppl.700
Language:
English
Publisher:
American Society of Clinical Oncology (ASCO)
Publication Date:
2018
detail.hit.zdb_id:
2005181-5
