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In rectal cancer,one of the most common cancers worldwide,the proper staging of the disease determines the subsequent therapy.For those with locally advancedrectal cancer,a neoadjuvant chemoradiotherapy(CRT) is recommended before any surgery.However,response to CRT ranges from complete response(responders) to complete resistance(non-responders).To date we are not able to separate in advance the first group from the second,due to the absence of a valid biomarker.Therefore all patients receive the same therapy regardless of whether they reap benefits.On the other hand almost all patients receive a surgical resection after the CRT,although a watch-and-wait procedure or an endoscopic resection might be sufficient for those who responded well to the CRT.Being highly conserved regulators of gene expression,micro RNAs(mi RNAs) seem to be promising candidates for biomarkers.Many studies have been analyzing the mi RNAs expressed in rectal cancer tissue to determine a specific mi RNA profile for the ailment.Unfortunately,there is only a small overlap of identified mi RNAs between different studies,posing the question as to whether different methods or differences in tissue storage may contribute to that fact or if the results simply are not reproducible,due to unknown factors with undetected influences on mi RNA expression.Other studies sought to find mi RNAs which correlate to clinical parameters(tumor grade,nodal stage,metastasis,survival) and therapy response.Although several mi RNAs seem to have an impact on the response to CRT or might predict nodal stage,there is still only little overlap between different studies.We here aimed to summarize the current literature on rectal cancer and mi RNA expression with respect to the different relevant clinical parameters.
In rectal cancer, one of the most common cancers worldwide, the proper staging of the disease determines the following therapy. For those with locally advancedrectal cancer, a neoadjuvant chemoradiotherapy (CRT) is recommended before any surgery. Host, response to CRT ranges from complete response (responders) to complete resistance (non-responders) .To date we are not able to separate in advance the first group from the second, due to the absence of a valid biomarker.Therefore all patients receive the same therapy regardless of whether they reap benefits. Of the other hand almost all patients receive a surgical resection after the CRT, although a watch-and-wait procedure or an endoscopic resection might be sufficient for those who who well well to the CRT. Being highly conserved regulators of gene expression, MicroRNAs (mi RNAs) seem to be promising candidates for biomarkers. Many studies have been analyzing the mi RNAs expressed in rectal cancer tissue to determine a specific mi RNA profile for the ailment. Unfortunately, there is only a small overlap of identified mi RNAs between different studies, posing the question as to whether different methods or differences in tissue storage may contribute to that fact or if the results simply are not reproducible, due to unknown factors with undetected influences on mi RNA expression. Other studies sought to find miRNAs which correlate to clinical parameters (tumor grade, nodal stage, metastasis, survival) and therapy response. Several seem to have an impact on the CRT or might predict nodal stage, there is still only little overlap overlap between different studies.We here aimed to summarize the current literature on rectal cancer and mi RNA expression with respect to the different relevant clinical parameters.