Publication Abstract

Authors: Levin TR, Corley DA, Jensen CD, Marks AR, Zhao WK, Zebrowski AM, Quinn VP, Browne LW, Taylor WR, Ahlquist DA, Lidgard GP, Berger BM

Title: Genetic Biomarker Prevalence Is Similar in Fecal Immunochemical Test Positive and Negative Colorectal Cancer Tissue.

Journal: Dig Dis Sci 62(3):678-688

Date: 2017 Mar

Abstract: BACKGROUND: Fecal immunochemical test (FIT) screening detects most asymptomatic colorectal cancers. Combining FIT screening with stool-based genetic biomarkers increases sensitivity for cancer, but whether DNA biomarkers (biomarkers) differ for cancers detected versus missed by FIT screening has not been evaluated in a community-based population. AIMS: To evaluate tissue biomarkers among Kaiser Permanente Northern California patients diagnosed with colorectal cancer within 2 years after FIT screening. METHODS: FIT-negative and FIT-positive colorectal cancer patients 50-77 years of age were matched on age, sex, and cancer stage. Adequate DNA was isolated from paraffin-embedded specimens in 210 FIT-negative and 211 FIT-positive patients. Quantitative allele-specific real-time target and signal amplification assays were performed for 7 K-ras mutations and 10 aberrantly methylated DNA biomarkers (NDRG4, BMP3, SFMBT2_895, SFMBT2_896, SFMBT2_897, CHST2_7890, PDGFD, VAV3, DTX1, CHST2_7889). RESULTS: One or more biomarkers were found in 414 of 421 CRCs (98.3%). Biomarker expression was not associated with FIT status, with the exception of higher SFMBT2_897 expression in FIT-negative (194 of 210; 92.4%) than in FIT-positive cancers (180 of 211; 85.3%; p = 0.02). There were no consistent differences in biomarker expression by FIT status within age, sex, stage, and cancer location subgroups. CONCLUSIONS: The biomarkers of a currently in-use multi-target stool DNA test (K-ras, NDRG4, and BMP3) and eight newly characterized methylated biomarkers were commonly expressed in tumor tissue specimens, independent of FIT result. Additional study using stool-based testing with these new biomarkers will allow assessment of sensitivity, specificity, and clinical utility.