p-values <0.1 were considered significant. The p-value cut-off of 0.1 was selected as this value represents a favorable compromise between false positive and true positive Epoxomicin clinical trial rates in the setting of background “noise” associated with the identification of differentially expressed candidate RNAs with microarray data . Tissue microarray data TLR4 staining intensity, surface area, and intensity score were correlated with clinico-pathologic endpoints. An arbitrary TLR4 intensity score of >3 was selected to denote positive TLR4 staining, with a score of >5 considered strongly positive. R software was used
to reveal relationships according to guidance provided by the CDP . Non-parametric Wilcoxon sum-rank tests were performed for non-normal distributions. Results Gene expression data 11 data sets met our strict entry criteria (Figure 1A).The most commonly included platform was an Affymetrix chip employing four distinct TLR4 probes (Figure 1B). For ease, we have relabeled these probes by transcript length: v1552798 = Short, v221060 = Medium, v232068 = Long1, and v224341 = Long2 (Figure 1C). Figure 1 Data Sets and Description of Probes with Corresponding Transcripts. A) Transcriptome data sets included in analysis with GSE Series Number as identified on GEO. Platform used,
colon tissue type studied, numbers of tissues included, and clinical endpoints are listed. B) TLR4 Gene and Transcripts. Assembly of known TLR4 gene and mRNA transcripts using University of California
at Santa Clara Genome Browser. The size of the transcript identified by the Protein Tyrosine Kinase inhibitor individual Affymetrix AC220 probes varies and we have denoted them as follows: v1552798aat (Short Probe), v232068sat (Long Probe 1), v224341xat (Long RVX-208 Probe 2), and v221060sat (Medium Probe). C) TLR4 Transcript Table. Description of known transcript variants by length of sequence and protein products where applicable. Complementary probes by platform manufacturer and antibodies for IHC are detailed. This table was adapted from Ensembl Genome Browser. Demographics and colonic tumor location Meaningful data regarding patient age at time of CRC diagnosis was available in four studies (GSE14333, GSE16125, GSE33113, and GSE31595). In one series, increasing age was associated with higher TLR4 expression, but the effect was minor with a regression coefficient (coef) = 1.02 (p = 0.018) (GSE14333) . In the remaining studies, no consistent relationship between age, gender, ethnicity, colonic location, and TLR4 expression was noted. No relationship between TLR4 and adenoma size was identified (GSE8671) . TLR4 expression is increased in colon adenomas and CRC In an effort to clarify the temporal relationship between TLR4 expression and colonic neoplasia, we identified data sets reporting normal tissue, adenomatous polyps, and CRC. Skrzypczak, et al. examined surgical specimens from 105 patients comparing CRC to matched normal tissue.