Colvera for Detection of Disease Recurrence

This is an observational, prospective comparison study, where blood is collected for assay of
methylated BCAT1 and IKZF1 DNA and CEA, from subjects who have undergone curative treatment
for primary CRC of stages II and III (AJCC) and who are in remission and scheduled for
follow-up radiological imaging as part of their surveillance program for recurrence.
Participation is for one visit only as part of each subject's surveillance-monitoring
schedule. Two K2-EDTA blood tubes and two PAXgene™ tubes will be collected Any evidence of
methylated BCAT1 and/or IKZF1 DNA in blood represents a Colvera "positive" result. CEA levels
of 5ug/L or higher will represent a "positive" result. Sensitivity and specificity of the
Colvera and CEA test will be estimated and compared in a paired fashion in each case where
recurrence status has been investigated and determined by the site clinical management team.
Blood testing shall be performed and analyzed by qualified staff blinded to clinical status.
This is a cross-sectional observational non-significant risk study, and test results will not
be used for clinical management, i.e. there will be no interventions in subjects consenting
to participate in this Research Study.

Inclusion Criteria:

1. Subject is 18 years or older, and capable and willing to provide informed consent.

2. Subject has undergone curative treatment for primary CRC of stages II and III (AJCC).

3. Subject has no clinical evidence of disease (NED) (after initial treatment)

4. Subject has concluded course of initial treatment for primary CRC (i.e. end of
surgery, chemotherapy and/or radiotherapy)

5. Subject is willing/able to provide a blood sample

Exclusion Criteria:

1. Subject has evidence of residual disease.

2. Subject has other organ cancer at the time of recruitment.

3. Subject has prior history of recurrent CRC.

4. Subject has concurrent serious non-neoplastic illness that makes enrollment
impractical or clinically inappropriate.

5. Subject is receiving chemo- or radiotherapy at the time of blood collection, or
between blood collection and radiological imaging.