Replication Study: <i>Fusobacterium nucleatum</i> infection is prevalent in human colorectal carcinoma.

Abstract

As part of the <ext-link ext-link-type="uri" xlink:href="https://osf.io/e81xl/wiki/home/">Reproducibility Project: Cancer Biology</ext-link>, we published a Registered Report (Repass et al., 2016), that described how we intended to replicate an experiment from the paper '<i>Fusobacterium nucleatum</i> infection is prevalent in human colorectal carcinoma' (Castellarin et al., 2012). Here we report the results. When measuring <i>Fusobacterium nucleatum</i> DNA by qPCR in colorectal carcinoma (CRC), adjacent normal tissue, and separate matched control tissue, we did not detect a signal for <i>F. nucleatum</i> in most samples: 25% of CRCs, 15% of adjacent normal, and 0% of matched control tissue were positive based on quantitative PCR (qPCR) and confirmed by sequencing of the qPCR products. When only samples with detectable <i>F. nucleatum</i> in CRC and adjacent normal tissue were compared, the difference was not statistically significant, while the original study reported a statistically significant increase in <i>F. nucleatum</i> expression in CRC compared to adjacent normal tissue (Figure 2; Castellarin et al., 2012). Finally, we report a meta-analysis of the result, which suggests <i>F. nucleatum</i> expression is increased in CRC, but is confounded by the inability to detect <i>F. nucleatum</i> in most samples. The difference in <i>F. nucleatum</i> expression between CRC and adjacent normal tissues was thus smaller than the original study, and not detected in most samples.