Circulating Tumor Cells in Patients With Rectal Cancer

Healthy Participants:

If you have not been diagnosed with colorectal cancer, blood (about 2 tablespoons) will be
drawn 1 time. This blood will be used as a control (normal) to look for differences in cells
in the blood of patients with colorectal cancer.

Once your blood is collected, your participation on this study will be over.

This study is for research purposes only. Test results will not be placed in your medical
record, and you will not be informed of the outcome of any test results.

enrolled in this study. All will be enrolled at MD Anderson.

Rectal Cancer Participants:

If you agree to take part in this study, you will have blood drawn to test for CTCs.

Rectal Cancer Participants:

If you are a participant who has been diagnosed with rectal (rectosigmoid) cancer, blood
(about 2 tablespoons) may be drawn 1 time before you start treatment.

Additional Blood Draws for Rectal Cancer Patients ONLY:

Blood (about 2 tablespoons) may also be drawn for CTC and other testing at the following time
points:

- Just before tumor surgery

- 1-8 weeks after your surgery, or before you begin chemotherapy

- 1-12 weeks after the last dose of chemotherapy

- 1 year after your surgery (+/- 12 weeks) OR 1 year after completion of treatment if you
are not having surgery

- 2 years after your surgery (+/- 12 weeks) OR 2 years after completion of treatment if
you are not having surgery

- If the disease gets worse during treatment OR If the disease comes back within 6 years
after treatment OR at end of 6 years follow-up

If there is a problem with your sample during testing AND you are still in one of the same
timepoints listed above, you may be asked to provide extra blood (about 2 tablespoons) to
complete the study testing. Whenever possible, this blood draw will be done as part of a
routine blood draw, but you may need to come to the clinic for this.

If you choose to receive follow-up care away from MD Anderson, you will be asked to allow
study staff to contact you by phone or email. You will be asked about the status of the
disease and you will be given instructions on how to provide blood samples for the time
points above.

Some of your processed blood samples and data may be sent to Natera for additional testing
related to this study. No identifying information about you will be included with these
samples. They will have a special number assigned so that the samples will not be connected
back to you by anyone outside of the research team at MD Anderson.

Inclusion Criteria:

1. Adult participants (Age >/= 18 years old)

2. Meets one of the following definitions:

1. Healthy Subject:

No known diagnosis of colorectal cancer (CRC) or any other type of cancer for the
last 10 years.(basal cell skin cancer is allowed)Subjects will be asked about
their cancer history and a verbal confirmation is required.

2. Any patient with diagnosis of rectal (or rectosigmoid) adenocarcinoma, including:

Patients with primary disease with or without neoadjuvant therapy; OR Patients with
recurrent disease with or without neoadjuvant therapy; OR Patients with metastatic
disease with or without prior treatment

3. No known current diagnosis of other cancer; if prior diagnosis of other cancer, he/she
has been free from cancer for >/= 6 years and is on no active treatment.

4. Adequate mental and language capacity to provide consent.

Exclusion Criteria: