Flagging Genes (Probesets) Associated with RD in Both TCGA and Tothill ====================================================================== by Keith A. Baggerly ## 1 Executive Summary ### 1.1 Introduction We want to identify genes whose expression shows a strong and similarly directed association with residual disease (RD) status in both the TCGA and Tothill datasets. ### 1.2 Methods We load our previously assembled RData files for tcgaExpression, tcgaFilteredData, tothillExpression, tothillFilteredData, and tothillClinical. We restrict our attention to probesets on both the TCGA and Tothill array platforms. Then, using just the filtered sets of samples, we contrast RD and No RD samples within each dataset using two sample t-tests. For each probeset in each dataset, we identify the associated gene and record the mean expression level in the RD and No RD groups, the t-statistic, the raw p-value, and the false discovery rate (FDR) adjusted p-value. We flag probsets that are significantly different in both TCGA and Tothill using (a) a 5% FDR cutoff and (b) a 10% FDR cutoff. We plot the bivariate t-tests to look for structure, expression heatmaps for the selected probes to look for patterns, correlations between the probes chosen to look for coordinated behavior, and dot and density plots for individual probesets to identify other features. We write a convenience function to make generation of the dot and density plots easier. ### 1.3 Results There are 22277 probesets common to the two platforms. We flag 8 probesets using a 5% FDR cutoff in both datasets, and 47 probesets using a 10% FDR cutoff. The bivariate plot of the t-statistics found is shown in Figure [1](#bivarTVals); a zoomed version highlighting the probesets overexpressed in RD samples is shown in Figure [2](#bivarTValsZoom). The expression heatmaps for TCGA and Tothill using the 5% FDR cutoffs are in Figures [3](#tcgaHeatmap05pct) and [4](#tothillHeatmap05pct), respectively. The expression heatmaps for TCGA and Tothill using the 10% FDR cutoffs are in Figures [5](#tcgaHeatmap10pct) and [6](#tothillHeatmap10pct), respectively. Heatmaps of the pairwise 10% FDR probe correlations for TCGA and Tothill are shown in Figures [7](#tcgaProbesetCors) and [8](#tothillProbesetCors). Dot and density plots for all 47 probesets passing the 10% FDR filter are saved as "plotsOfTop47Probesets.pdf" in the Reports folder. Dot and density plots for 6 probesets, corresponding to LUM, DCN, GADD45B, FABP4, ADH1B, and ADIPOQ are shown in Figures [9](#lum), [10](#dcn), [11](#gadd45b), [12](#fabp4), [13](#adh1b), and [14](#adipoq), respectively. We save tcgaCommonUsed, tothillCommonUsed, keyProbesets05pct, keyGenes05pct, keyProbesets10pct, keyGenes10pct, nTCGANoRD, nTCGARD, nTothillNoRD, nTothillRD, plotProbesetResults, and rdTTestResults to the RData file "rdFlaggedGenes.RData". ### 1.4 Conclusions In both sets of expression heatmaps, there is evidence of a molecularly distinct subset of patients (about a third) with a higher chance of having RD. Expression levels for most of the genes identified are consistently higher in these patients. For LUM, DCN, and GADD45B, which represent the bulk of the probsets showing elevation, what we see is an overall mean shift (values are trending higher) without a clear division point (above here, something's changed). For FABP4, ADH1B, and (to a lesser extent) ADIPOQ, we see a *qualitative* shift in a smaller subset -- values for most samples are very low (effectively "off""), but values for a subset of patients are very high ("on""). A qualitative difference strikes us as more likely to survive a shift across assays than a mean offset, so we preferentially pursue FABP4 and ADH1B. ## 2 Libraries We first load the libraries we will use in this report. ```{r libraries, message=FALSE} library(affy) library(hthgu133a.db) library(gplots) ``` ## 3 Loading the Data Here we simply load the previously assembled RData files. clinical information and expression matrices, and skim the first line of the clinical information to see what variables exist for filtering the samples. ```{r loadTCGARData} load(file.path("RDataObjects","tcgaExpression.RData")) load(file.path("RDataObjects","tcgaFilteredSamples.RData")) load(file.path("RDataObjects","tothillExpression.RData")) load(file.path("RDataObjects","tothillFilteredSamples.RData")) load(file.path("RDataObjects","tothillClinical.RData")) ``` ## 4 Rearranging Data ### 4.1 Selecting Common Probesets We only want to examine probesets evaluated in both datasets. ```{r findCommonProbes} commonProbesets <- intersect(rownames(tcgaExpression),rownames(tothillExpression)) ``` ### 4.2 Extracting RD and No RD Samples Given the common probesets, we next get matrices of data for RD and No RD measurements for both TCGA and Tothill. We begin with TCGA ```{r getTCGACommonRD} tcgaCommonRD <- tcgaExpression[commonProbesets, names(tcgaSampleRD)[which((tcgaSampleRD=="RD") & (tcgaFilteredSamples[,"sampleUse"]=="Used"))]] dim(tcgaCommonRD) tcgaCommonNoRD <- tcgaExpression[commonProbesets, names(tcgaSampleRD)[which((tcgaSampleRD=="No RD") & (tcgaFilteredSamples[,"sampleUse"]=="Used"))]] dim(tcgaCommonNoRD) ``` Next, we repeat the process for Tothill. ```{r getTothillCommonRD} tothillCommonRD <- tothillExpression[commonProbesets, names(tothillRD)[which((tothillRD=="RD") & (tothillFilteredSamples[,"sampleUse"]=="Used"))]] dim(tothillCommonRD) tothillCommonNoRD <- tothillExpression[commonProbesets, names(tothillRD)[which((tothillRD=="No RD") & (tothillFilteredSamples[,"sampleUse"]=="Used"))]] dim(tothillCommonNoRD) ``` ### 4.3 Bundling For later plots, it can be easier to rearrange things yet again. ```{r bundleMatrices} tcgaCommonUsed <- cbind(tcgaCommonNoRD,tcgaCommonRD) tothillCommonUsed <- cbind(tothillCommonNoRD,tothillCommonRD) ``` ## 5 Contrasting RD with No RD: T-Tests ### 5.1 Running T-Tests Our first comparisons involve simple two-sample t-tests. We perform these for TCGA first. ```{r tcgaTTests} d1 <- date() tcgaTVals <- rep(0,length(commonProbesets)) names(tcgaTVals) <- commonProbesets tcgaPVals <- tcgaTVals for(i1 in 1:length(commonProbesets)){ tempT <- t.test(tcgaCommonRD[i1,],tcgaCommonNoRD[i1,],var.equal=TRUE) tcgaTVals[i1] <- tempT[["statistic"]] tcgaPVals[i1] <- tempT[["p.value"]] } d2 <- date() c(d1,d2) tcgaPValsAdj <- p.adjust(tcgaPVals,method="fdr") names(tcgaPValsAdj) <- commonProbesets ``` Then we repeat the process with Tothill. ```{r tothillTTests} d1 <- date() tothillTVals <- rep(0,length(commonProbesets)) names(tothillTVals) <- commonProbesets tothillPVals <- tothillTVals for(i1 in 1:length(commonProbesets)){ tempT <- t.test(tothillCommonRD[i1,],tothillCommonNoRD[i1,],var.equal=TRUE) tothillTVals[i1] <- tempT[["statistic"]] tothillPVals[i1] <- tempT[["p.value"]] } d2 <- date() c(d1,d2) tothillPValsAdj <- p.adjust(tothillPVals,method="fdr") names(tothillPValsAdj) <- commonProbesets ``` ### 5.2 Checking for Overlap at an Extreme Cutoff We now see which genes (if any) appear significant at an FDR of 5% in both datasets. ```{r check5pct} sum(tcgaPValsAdj < 0.05) sum(tothillPValsAdj < 0.05) sum((tothillPValsAdj < 0.05) & (tcgaPValsAdj < 0.05)) sum((tothillPValsAdj < 0.1) & (tcgaPValsAdj < 0.1)) keyProbesets05pct <- names(which((tothillPValsAdj < 0.05) & (tcgaPValsAdj < 0.05))) keyProbesets10pct <- names(which((tothillPValsAdj < 0.1) & (tcgaPValsAdj < 0.1))) keyGenes05pct <- unlist(mget(keyProbesets05pct, hthgu133aSYMBOL)) keyGenes10pct <- unlist(mget(keyProbesets10pct, hthgu133aSYMBOL)) keyGenes05pct ``` There are 8 probesets flagged at a common FDR of 5% (listed above), and 47 probesets flagged at a common FDR of 10%. ### 5.3 Building a Data Frame Now we bundle our t-test results into a data frame for later reference, sorting the entries by mean fdr-adjusted p-value. ```{r buildDataFrame} tcgaMeanRD <- apply(tcgaCommonRD,1,mean) tcgaMeanNoRD <- apply(tcgaCommonNoRD,1,mean) tothillMeanRD <- apply(tothillCommonRD,1,mean) tothillMeanNoRD <- apply(tothillCommonNoRD,1,mean) commonGeneSymbols <- unlist(mget(commonProbesets, hthgu133aSYMBOL)) rdTTestResults <- data.frame(row.names=rownames(tcgaCommonUsed), geneSymbol=commonGeneSymbols, tcgaMeanRD=tcgaMeanRD, tcgaMeanNoRD=tcgaMeanNoRD, tcgaTVals=tcgaTVals, tcgaPVals=tcgaPVals, tcgaPValsAdj=tcgaPValsAdj, tothillMeanRD=tothillMeanRD, tothillMeanNoRD=tothillMeanNoRD, tothillTVals=tothillTVals, tothillPVals=tothillPVals, tothillPValsAdj=tothillPValsAdj) rdTTestResults <- rdTTestResults[order(tcgaPValsAdj + tothillPValsAdj),] ``` As a check, we look at the results for the top 10 probesets by this ordering. ```{r checkTop10Probesets} rdTTestResults[1:10,] ``` ## 6 Plotting Data Given the contrast results, we now plot the data in several ways to see if this clarifies aspects of the structure. ### 6.1 Bivariate t-value Plot Our first check involves plotting the TCGA and Tothill t-statistics against each other, to see if there are clear outliers or disagreement with respect to sign. The initial plot, Figure [1](#bivarTVals), shows the vast majority of the probesets selected are more strongly expressed in RD samples. A zoom on the upper quadrant of this plot is shown in Figure [2](#bivarTValsZoom). ```{r plotBivarTVals, fig.show='asis', echo=FALSE} tcgaCut05pct <- (min(abs(tcgaTVals)[tcgaPValsAdj <= 0.05]) + max(abs(tcgaTVals)[tcgaPValsAdj > 0.05]))/2 tcgaCut10pct <- (min(abs(tcgaTVals)[tcgaPValsAdj <= 0.1]) + max(abs(tcgaTVals)[tcgaPValsAdj > 0.1]))/2 tothillCut05pct <- (min(abs(tothillTVals)[tothillPValsAdj <= 0.05]) + max(abs(tothillTVals)[tothillPValsAdj > 0.05]))/2 tothillCut10pct <- (min(abs(tothillTVals)[tothillPValsAdj <= 0.1]) + max(abs(tothillTVals)[tothillPValsAdj > 0.1]))/2 smoothScatter(tcgaTVals, tothillTVals, xlab="TCGA", ylab="Tothill", main="T-Tests, RD-No RD, 5% and 10% FDRs Shown") abline(h=c(-1,1)*tothillCut05pct,col="red") abline(h=c(-1,1)*tothillCut10pct,col="black") abline(v=c(-1,1)*tcgaCut05pct,col="red") abline(v=c(-1,1)*tcgaCut10pct,col="black") points(tcgaTVals[keyProbesets10pct],tothillTVals[keyProbesets10pct], pch="*",col="black") text(tcgaTVals[keyProbesets10pct],tothillTVals[keyProbesets10pct], labels=keyGenes10pct,cex=0.5,col="black",adj=c(0,0)) points(tcgaTVals[keyProbesets05pct],tothillTVals[keyProbesets05pct], pch="*",col="red") text(tcgaTVals[keyProbesets05pct],tothillTVals[keyProbesets05pct], labels=keyGenes05pct,cex=0.5,col="red",adj=c(0,0)) ```

Figure 1: Bivariate plot of two-sample RD-No RD t-values for TCGA and Tothill. The vast majority of the probesets selected show higher expression in RD cases. Lumican (LUM) is the strongest overall.

```{r plotBivarTValsZoom, fig.show='asis', echo=FALSE} smoothScatter(tcgaTVals, tothillTVals, xlab="TCGA", ylab="Tothill", main="T-Tests, RD-No RD, Upper Quadrant Zoom", xlim=c(3,6),ylim=c(3.3,5.2)) abline(h=c(-1,1)*tothillCut05pct,col="red") abline(h=c(-1,1)*tothillCut10pct,col="black") abline(v=c(-1,1)*tcgaCut05pct,col="red") abline(v=c(-1,1)*tcgaCut10pct,col="black") points(tcgaTVals[keyProbesets10pct],tothillTVals[keyProbesets10pct], pch="*",col="black") text(tcgaTVals[keyProbesets10pct],tothillTVals[keyProbesets10pct], labels=keyGenes10pct,cex=0.7,col="black",adj=c(0,0)) points(tcgaTVals[keyProbesets05pct],tothillTVals[keyProbesets05pct], pch="*",col="red") text(tcgaTVals[keyProbesets05pct],tothillTVals[keyProbesets05pct], labels=keyGenes05pct,cex=0.7,col="red",adj=c(0,0)) ```

Figure 2: Zoom on the upper quadrant of the bivariate plot of two-sample RD-No RD t-values for TCGA and Tothill, to show the names more clearly.

### 6.2 Heatmaps of Probesets Flagged by 5% FDR We want to see if the most clearly chosen probesets are flagging the same samples, and how clearly they divide RD from No RD cases. We check this first for the 8 probesets passing the 5% FDR filters. The TCGA heatmap is shown in Figure [3](#tcgaHeatmap05pct), and the Tothill heatmap is shown in Figure [4](#tothillHeatmap05pct). The general story is the same in both; we see a clear cluster in which most of the probesets are concurrently elevated, and the patients in these clusters have much higher rates of RD. Of the 8 probesets examined, those for FABP4 and ADH1B stand out as telling the story most starkly, though the enrichment rates may not be much higher. We do not see a tight grouping of the No RD cases, but this is to be expected since some cases of RD will not be driven at the molecular level but rather by spatial positioning in the abdomen. ```{r plotTCGA05pctHeatmap, echo=FALSE} nTCGANoRD <- ncol(tcgaCommonNoRD) nTCGARD <- ncol(tcgaCommonRD) heatmap.2(tcgaCommonUsed[keyProbesets05pct,], scale="row", trace="none", labRow=keyGenes05pct, labCol="", col=bluered, ColSideColors=c(rep("blue",nTCGANoRD),rep("red",nTCGARD)), xlab="TCGA Samples", cexRow=0.7) ```

Figure 3: Heatmap of the TCGA Samples using just the 8 probesets passing the 5% FDR filter for both TCGA and Tothill. RD status (Red=RD, Blue=No RD) is indicated in the colorbar at top. There is a clear cluster at the left in which most of these genes are concurrently elevated; the density of RD cases is much higher in this group. Of the probesets shown, FABP4 and ADH1B stand out from the rest in that they show a much more marked "on/off" pattern.

```{r plotTothill05pctHeatmap, echo=FALSE} nTothillNoRD <- ncol(tothillCommonNoRD) nTothillRD <- ncol(tothillCommonRD) heatmap.2(tothillCommonUsed[keyProbesets05pct,], scale="row", trace="none", labRow=keyGenes05pct, labCol="", col=bluered, ColSideColors=c(rep("blue",nTothillNoRD),rep("red",nTothillRD)), xlab="Tothill Samples", cexRow=0.7) ```

Figure 4: Heatmap of the Tothill Samples using just the 8 probesets passing the 5% FDR filter for both TCGA and Tothill. RD status (Red=RD, Blue=No RD) is indicated in the colorbar at top. The story essentially parallels that for the TCGA data. There is a clear cluster at the right in which most of these genes are concurrently elevated; the density of RD cases is much higher in this group. Of the probesets shown, FABP4 and ADH1B stand out from the rest in that they show a much more marked "on/off" pattern.

### 6.3 Heatmaps of Probesets Flagged by 10% FDR Having examined the 5% FDR probesets, we now expand our view to encompass probesets passing a 10% FDR filter in both TCGA and Tothill. The TCGA heatmap is shown in Figure [5](#tcgaHeatmap10pct), and the Tothill heatmap is shown in Figure [6](#tothillHeatmap10pct). One factor that becomes more apparent here is the broadly parallel pattern of overexpression seen for most of the probesets (FABP4 and ADH1B again stand out). This suggests there may be a common driver for many of them; possibly a "pathway" of some type. ```{r plotTCGA10pctHeatmap, echo=FALSE} heatmap.2(tcgaCommonUsed[keyProbesets10pct,], scale="row", trace="none", labRow=keyGenes10pct, labCol="", col=bluered, ColSideColors=c(rep("blue",nTCGANoRD),rep("red",nTCGARD)), xlab="TCGA Samples", cexRow=0.7) ```

Figure 5: Heatmap of the TCGA Samples using the 47 probesets passing the 10% FDR filter for both TCGA and Tothill. RD status (Red=RD, Blue=No RD) is indicated in the colorbar at top. While FABP4, ADH1B, and, to a lesser extent ADIPOQ again stand out, the main visual impression is one of parallel expression for most of the probesets, suggesting some common underlying driving factor.

```{r plotTothill10pctHeatmap, echo=FALSE} heatmap.2(tothillCommonUsed[keyProbesets10pct,], scale="row", trace="none", labRow=keyGenes10pct, labCol="", col=bluered, ColSideColors=c(rep("blue",nTothillNoRD),rep("red",nTothillRD)), xlab="Tothill Samples", cexRow=0.7) ```

Figure 6: Heatmap of the Tothill Samples using the 47 probesets passing the 10% FDR filter for both TCGA and Tothill. RD status (Red=RD, Blue=No RD) is indicated in the colorbar at top. As with the TCGA data, While FABP4, and ADH1B again stand out, the main visual impression is one of parallel expression for most of the probesets, suggesting some common underlying driving factor.

### 6.4 Heatmaps of Correlation of Probesets Flagged by 10% FDR Given the broad parallelism of expression seen in the heatmaps of probesets passing the 10% FDR filters, we want to check the correlation patterns between these probes. The TCGA heatmap is shown in Figure [7](#tcgaProbesetCors), and the Tothill heatmap is shown in Figure [8](#tothillProbesetCors). ```{r plotTCGAProbesetCors, echo=FALSE} tcgaCors <- cor(t(tcgaCommonUsed[keyProbesets10pct,])) heatmap.2(tcgaCors, trace="none", labRow=keyGenes10pct, col=bluered) ```

Figure 7: Correlations in the TCGA data between the 47 probesets selected by 10% FDR cutoffs. While the three probesets where expression declines drive the coloring most, the main story in terms of commonality may be the grouping of 26 probesets in the upper right, including lumican (LUM) and decorin (DCN). Cutting the probsets into three clusters overall, FABP4 and ADH1B reside in the second grouping of probesets at the right.

```{r plotTothillProbesetCors, echo=FALSE} tothillCors <- cor(t(tothillCommonUsed[keyProbesets10pct,])) heatmap.2(tothillCors, trace="none", labRow=keyGenes10pct, col=bluered) ```

Figure 8: Correlations in the Tothill data between the 47 probesets selected by 10% FDR cutoffs. While the three probesets where expression declines drive the coloring most, the main story in terms of commonality may be the tight grouping of 31 probesets in the upper right, including lumican (LUM) and decorin (DCN). FABP4 and ADH1B reside in the second grouping of probesets at the right.

### 6.5 Density Plots and Dotplots We know some of the probesets are of interest. Now we look at aspects of behavior of the individual probesets, specifically dotplots and density plots for each probeset by dataset. First, we construct a generic function for plotting these results for a given probeset. ```{r plotProbesetResults} plotProbesetResults <- function(probesetID){ par(mfrow=c(2,2)) geneName <- unlist(mget(probesetID, hthgu133aSYMBOL)) plot(tcgaCommonUsed[probesetID,], col=c(rep("blue",nTCGANoRD),rep("red",nTCGARD)), xlab="TCGA Samples", ylab="Expression", main=paste("Expression of",geneName,"in TCGA")) abline(v=nTCGANoRD+0.5) plot(tothillCommonUsed[probesetID,], col=c(rep("blue",nTothillNoRD),rep("red",nTothillRD)), xlab="Tothill Samples", ylab="Expression", main=paste("Expression of",geneName,"in Tothill")) abline(v=nTothillNoRD+0.5) tempDensTCGA <- density(tcgaCommonUsed[probesetID,]) tempDensTCGANoRD <- density(tcgaCommonNoRD[probesetID,]) tempDensTCGARD <- density(tcgaCommonRD[probesetID,]) plot(tempDensTCGA[["x"]], tempDensTCGA[["y"]], xlab=paste("Expression of", probesetID, "in TCGA"), ylab="Density", type="l", main=paste("Density of",probesetID,"in TCGA")) lines(tempDensTCGANoRD[["x"]], (nTCGANoRD/(nTCGANoRD+nTCGARD)) * tempDensTCGANoRD[["y"]], col="blue") lines(tempDensTCGARD[["x"]], (nTCGARD/(nTCGANoRD+nTCGARD)) * tempDensTCGARD[["y"]], col="red") tempDensTothill <- density(tothillCommonUsed[probesetID,]) tempDensTothillNoRD <- density(tothillCommonNoRD[probesetID,]) tempDensTothillRD <- density(tothillCommonRD[probesetID,]) plot(tempDensTothill[["x"]], tempDensTothill[["y"]], xlab=paste("Expression of", probesetID, "in Tothill"), ylab="Density", type="l", main=paste("Density of",probesetID,"in Tothill")) lines(tempDensTothillNoRD[["x"]], (nTothillNoRD/(nTothillNoRD+nTothillRD)) * tempDensTothillNoRD[["y"]], col="blue") lines(tempDensTothillRD[["x"]], (nTothillRD/(nTothillNoRD+nTothillRD)) * tempDensTothillRD[["y"]], col="red") par(mfrow=c(1,1)) } ``` For reference, we produce a pdf file containing the results for all 47 probesets in our top list. ```{r outputTop47} pdf(file=file.path("Reports","plotsOfTop47Probesets.pdf")) for(i1 in 1:length(keyProbesets10pct)){ plotProbesetResults(keyProbesets10pct[i1]) } dev.off() ``` We include results for a few selected genes here: LUM (201744\_s\_at), Figure [9](#lum), DCN (211896\_s\_at), Figure [10](#dcn), GADD45B (207574\_s\_at), Figure [11](#gadd45b), FABP4 (203980\_at), Figure [12](#fabp4), ADH1B (209613\_s\_at), Figure [13](#adh1b), and ADIPOQ (207175\_at), Figure [14](#adipoq). For some of the genes (ADH1B, DCN), mutliple probesets are available but the results appear qualitatively similar to the representative ones chosen. For LUM, DCN, and GADD45B, which represent the bulk of the probsets showing elevation, what we see is an overall mean shift (values are trending higher) without a clear division point (above here, something's changed). For FABP4, ADH1B, and (to a lesser extent) ADIPOQ, we see a qualitative shift -- values for most samples are very low (effectively "off""), but values for a subset of patients are very high ("on""). This type of qualitative difference strikes us as more likely to survive a shift across assays than a mean offset, so we will preferentially pursue FABP4 and ADH1B. ```{r plotLUM, echo=FALSE} plotProbesetResults("201744_s_at") ```

Figure 9: Dot and density plots for lumican (LUM) in TCGA and Tothill. Cases with No RD are blue, RD are red. While there is a clear mean shift (which drives the t-test results), there is not a clearly defined cutpoint.

```{r plotDCN, echo=FALSE} plotProbesetResults("211896_s_at") ```

Figure 10: Dot and density plots for decorin (DCN) in TCGA and Tothill. Cases with No RD are blue, RD are red. While there is a clear mean shift (which drives the t-test results), there is not a clearly defined cutpoint.

```{r plotGADD45B, echo=FALSE} plotProbesetResults("207574_s_at") ```

Figure 11: Dot and density plots for GADD45B in TCGA and Tothill. Cases with No RD are blue, RD are red. While there is a clear mean shift (which drives the t-test results), there is not a clearly defined cutpoint.

```{r plotFABP4, echo=FALSE} plotProbesetResults("203980_at") ```

Figure 12: Dot and density plots for FABP4 in TCGA and Tothill. Cases with No RD are blue, RD are red. There is a qualitative shift in a subset of the patients.

```{r plotADH1B, echo=FALSE} plotProbesetResults("209613_s_at") ```

Figure 13: Dot and density plots for ADH1B in TCGA and Tothill. Cases with No RD are blue, RD are red. There is a qualitative shift in a subset of the patients.

```{r plotADIPOQ, echo=FALSE} plotProbesetResults("207175_at") ```

Figure 14: Dot and density plots for ADIPOQ in TCGA and Tothill. Cases with No RD are blue, RD are red. There is a qualitative shift in a subset of the patients.

## 7 Saving RData Now we save the relevant information to an RData object. ```{r saveRDFlaggedGenes} save(tcgaCommonUsed, tothillCommonUsed, keyProbesets05pct, keyGenes05pct, keyProbesets10pct, keyGenes10pct, nTCGANoRD, nTCGARD, nTothillNoRD, nTothillRD, plotProbesetResults, rdTTestResults, file=file.path("RDataObjects","rdFlaggedGenes.RData")) ``` ## 8 Appendix ### 8.1 File Location ```{r getLocation} getwd() ``` ## 8.2 SessionInfo ```{r sessionInfo} sessionInfo(); ```