RecruitingDiagnostic testExosomes in Rectal CancerThe primary aims of this study is to characterize exosomal biomarker levels in patients with locally advanced rectal cancer undergoing neoadjuvant chemoradiation therapy. Compare rates of exosomal expression before during and after chemoradiation therapy with pathologic response rates at the time of APR or LAR. The researchers will also examine the functionality of these exosomes in malignant colonic organoids and mouse models of colorectal cancer.