Abstract 1157: Increased expression of RecQ helicases in sporadic primary colorectal cancers

The RecQ helicase family of enzymes regulate nucleic acid metabolism through the major activity of unwinding double stranded nucleic acids. Heritable loss of RECQ helicase expression results in human syndromes associated with an elevated risk of cancers including colorectal cancer (CRC). In vitro studies have shown that loss of function of WRN and/or BLM increases sensitivity to killing by DNA damaging chemotherapeutic agents. Thus, over-expression of these helicases may mediate tumor resistance to DNA damaging chemotherapeutic agents, whereas under-expression may identify a population of tumors that may be more susceptible. Currently, the literature with regards to the expression status of these enzymes in CRC is sparse. In this study, we assess the expression of all five members of the RECQ helicase family (WRN, BLM, RECQL, RECQL4 and RECQL5) in 32 sporadic primary colorectal cancer cases with matched normal colonic mucosa using quantitative real-time PCR. The results show a significant increase in the fold change of RECQ helicase expression in tumor as compared to the matched normal mucosa, using the Wilcoxon Signed Rank test with a theoretical median of 1. The results are as follows: WRN median=1.191, mean=1.347, SD=0.6189, p-value=0.0043; BLM median=4.146, mean=12.88, SD=24.86, p-value < 0.0001;RecQL median=1.638, mean=1.806, SD=1.145, p-value=0.0002;RecQL4 median=4.384, mean=4.745, SD=4.167, p-value