Biomarkers of Risk for Colorectal Neoplasia (Team Project #2)

Abbreviated Name
Colon Team Project #2
Lead Investigator
Schoen, Robert E.University of Pittsburgh Cancer Institute
Coordinating Investigator
Schoen, Robert E. University of Pittsburgh Cancer Institute
Involved Investigators


No abstract availalbe.


1.   Characterization of intra-subject reproducibility and variability: To assess the reproducibility and variability of marker expression within individuals, we will evaluate marker expression in duplicate samples from the same region of the colon and in 4 different sites around the colon, the rectum, left, transverse and right colon. 2.   Characterization of inter-subject variability in marker expression by disease phenotype: To characterize the inter-subject variability in marker expression by disease phenotype, we will compare marker expression in normal colonic mucosa between subjects with and without adenomatous polyps. 3.   Characterization of the relationship of marker expression and long-term adenoma recurrence: To examine the relationship between marker expression and long-term adenoma recurrence, we will compare marker expression among subjects with baseline adenomas who have a recurrence of adenomatous polyps compared to those who do not.

Analytic Method

Analysis Plan: A mixed effects linear model will be used to estimate means and between-patient and within-segment variance parameters; location of biopsy will be considered a fixed effect, and patient a random effect. The within-segment variance is an estimator of assay reliability, while the difference in means between segments indicates how well rectal or distal colon values agree with transverse and proximal colon values. The between-patient variances can be used to calculate effect sizes used in the design of subsequent trials. The biopsy location effect is an indicator of the consistency of the biomarkers throughout the colon; because these are normal tissue, not adenoma, biopsies, significant variation between biopsy sites would have implications for sampling strategies, and could indicate non-specificity of the marker for adenoma. Using Monte Carlo simulation of the proposed design, we determined that, in 90% of the simulated trials, the estimated between-patient variance was within 70% of the true value, and the estimated within-segment variance was within 28% of its true value. The power to test the null hypothesis of no difference in means between segments was in excess of 80% if the effect size (difference between segment means divided by within-segment standard deviation) was 0.8 or greater.


  • No publications available at this time for this protocol.


  • No biomarkers available at this time for this protocol.

Data Collections

  • No data collections available at this time for this protocol.
 Team Project
Start Date
Sep 1 2011
Estimated Finish Date
Sep 1 2014
Protocol ID
Protocol Type
Fields of Research
  • Genomics
  • Proteomics
Collaborative Group
G.I. and Other Associated Cancers Research Group
Cancer Types
  • Malignant neoplasm of colon
Phased Status

Associated Forms