This feasibility trial will evaluate the ability of the SuMO Tissue Access and Resection System (Apollo Endosurgery, Austin, Texas). The SuMO System utilizes balloons to create a submucosal pocket and electrosurgical cutting device to resect the mucosa. The SuMO elevates the tissue from the underlying muscularis using a balloon to distend the submucosa, similar to what is currently performed with injectable saline in a standard EMR. After dissection of the lesion, a separate cutting device will be utilized to resect the tissue by cutting around the border of the targeted tissue. If needed, a standard loop snare will be used to complete the mucosal resection.

The subject will already be scheduled for segmental colectomy or gastrectomy.

The colectomy or gastrectomy specimen will be prepared on a side table for an ex vivo endoscopic procedure. The ends of the stomach or colon, if not already stapled closed will be ligated to allow for insufflation. The endoscope will be placed into the excised organ and the SuMO System devices will be deployed away from any areas of excised pathologic tissue, so as not to disrupt the pathologist's evaluation of the excised tissue. The specimen will then be opened and grossly examined for the actual completeness of the submucosal pocket and resection. Mucosal and muscular wall disruptions will be assessed. Again, no interference in the underlying pathology will be performed. If sufficient specimen is present, the SuMO procedure may be repeated on the same specimen.

Following the performance of the EMR by the SUMO balloon system on the ex vivo colon specimen, both the resected piece of tissue and the site of resection will be evaluated pathologically by H and E staining. Specifically, the depth of resection in the ex vivo colon specimen will be determined. In addition, the level of dissection on the removed piece of mucosa will also be identified.

During this procedure still images or a video recording maybe captured, however all images will be taken of the removed specimen. There will not be any patient identifiers on any of the images or DVD's taken during the procedure.

No clinical follow up is required, as the treated area will have already been resected and there is no risk to the patient.

Inclusion Criteria:

• Male or female over 18 years of age
• Established indication for open or laparoscopic or colon resection or gastrectomy
• Subject agrees to participate, fully understands content of informed consent form, and signs the informed consent form

Exclusion Criteria:

• Subjects that are minors or prisoners
• Subjects who would have difficulty comprehending or complying with the requirements of the study
• Subjects who fail to give informed consent