Observational StudyMolecular Determinants of Response to Preoperative Therapy in Patients With Locally Advanced Colorectal Cancer

Inclusion Criteria:

1. Patients with colorectal adenocarcinoma (diagnosis based on either MDACC or outside records)
2. Patients scheduled to undergo neoadjuvant therapy per MDACC care team.
3. Patients over 18 years of age.
4. Patients with distant organ findings deemed to be indeterminate or metastatic will be enrolled at the surgeon's discretion.
5. Patients who have been deemed medically safe to undergo endoscopic biopsy by the physician performing the procedure.
6. Patients who would have typically undergone preoperative therapy followed by surgery but for specific reasons at the discretion of the treating physician underwent surgery without preoperative therapy may be enrolled at the surgeons' discretion.

Exclusion Criteria:

N/A