TCGA（转录组）差异分析三大R包及其结果对比 / 四六文摘

最近我们最优秀的R语言讲师小洁也开启了TCGA知识库打卡之旅，分享一下她其中一个学习成果，TCGA（转录组）差异分析三大R包及其结果对比。

如果你跟着她的教程学会了相关分析，可以尝试完成一个学徒作业：理解RNA-seq表达矩阵的两个形式

TCGA数据库背景知识推文合辑

众所周知,TCGA数据库是目前最综合最全面的癌症病人相关组学数据库，包括：

DNA Sequencing
miRNA Sequencing
Protein Expression array
mRNA Sequencing
Total RNA Sequencing
Array-based Expression
DNA Methylation
Copy Number array

知名的肿瘤研究机构都有着自己的TCGA数据库探索工具，比如：

Broad Institute FireBrowse portal, The Broad Institute
cBioPortal for Cancer Genomics, Memorial Sloan-Kettering Cancer Center

所以我挑选了部分，写了6个数据下载系列教程：

TCGA的28篇教程- 使用R语言的cgdsr包获取TCGA数据（cBioPortal）
TCGA的28篇教程- 使用R语言的RTCGA包获取TCGA数据（离线打包版本）
TCGA的28篇教程-使用R语言的RTCGAToolbox包获取TCGA数据（FireBrowse portal）
TCGA的28篇教程- 批量下载TCGA所有数据（ UCSC的 XENA）
TCGA的28篇教程-数据下载就到此为止吧
TCGA的28篇教程-整理GDC下载的xml格式的临床资料

虽然说，教程是关于TCGA数据库的不同数据的下载，实际上是希望可以帮助大家认识TCGA数据库的全貌，然后根据大家的提问，我也扩充了部分常见的TCGA数据库用法：

下面开始小洁的表演

1.准备R包

if(!require(stringr))install.packages('stringr') if(!require(ggplotify))install.packages("ggplotify") if(!require(patchwork))install.packages("patchwork") if(!require(cowplot))install.packages("cowplot") if(!require(DESeq2))install.packages('DESeq2') if(!require(edgeR))install.packages('edgeR') if(!require(limma))install.packages('limma')## 点评：这样的R包安装方法是有问题,大家自行思考一下

2.准备数据

本示例的数据是TCGA-KIRC的miRNA表达矩阵。tcga样本编号14-15位是隐藏分组信息的,详见：准考证号，身份证号码，TCGA样本条形码的区别

这里需要注意的是miRNA也是测序拿到的表达矩阵,所以分析等同于RNA-seq得到表达矩阵，一定要跟芯片数据分析区分开来哦！！！

rm(list = ls()) load("tcga_kirc_exp.Rdata") #表达矩阵expr dim(expr)## [1] 552 593group_list <- ifelse(as.numeric(str_sub(colnames(expr),14,15))<10,"tumor","normal") group_list <- factor(group_list,levels = c("normal","tumor")) table(group_list)## group_list ## normal tumor ## 71 522

3.三大R包的差异分析

3.1 Deseq2

library(DESeq2) colData <- data.frame(row.names =colnames(expr), condition=group_list) dds <- DESeqDataSetFromMatrix( countData = expr, colData = colData, design = ~ condition) #参考因子应该是对照组 dds$condition <- relevel(dds$condition, ref = "untrt")


dds <- DESeq(dds)

# 两两比较

res <- results(dds, contrast = c("condition",rev(levels(group_list))))

resOrdered <- res[order(res$pvalue),] # 按照P值排序

DEG <- as.data.frame(resOrdered)

head(DEG)

# 去除NA值

DEG <- na.omit(DEG)
#添加change列标记基因上调下调

#logFC_cutoff <- with(DEG,mean(abs(log2FoldChange)) + 2*sd(abs(log2FoldChange)) )

logFC_cutoff <- 1

DEG$change = as.factor(

  ifelse(DEG$pvalue < 0.05 & abs(DEG$log2FoldChange) > logFC_cutoff,

         ifelse(DEG$log2FoldChange > logFC_cutoff ,'UP','DOWN'),'NOT')

)

head(DEG)

DESeq2_DEG <- DEG

3.2 edgeR

library(edgeR)


dge <- DGEList(counts=expr,group=group_list)

dge$samples$lib.size <- colSums(dge$counts)

dge <- calcNormFactors(dge)
design <- model.matrix(~0+group_list)

rownames(design)<-colnames(dge)

colnames(design)<-levels(group_list)
dge <- estimateGLMCommonDisp(dge,design)

dge <- estimateGLMTrendedDisp(dge, design)

dge <- estimateGLMTagwiseDisp(dge, design)
fit <- glmFit(dge, design)

fit2 <- glmLRT(fit, contrast=c(-1,1))

DEG=topTags(fit2, n=nrow(expr)) DEG=as.data.frame(DEG) logFC_cutoff <- with(DEG,mean(abs(logFC)) + 2*sd(abs(logFC)) ) logFC_cutoff <- 1 DEG$change = as.factor( ifelse(DEG$PValue < 0.05 & abs(DEG$logFC) > logFC_cutoff, ifelse(DEG$logFC > logFC_cutoff ,'UP','DOWN'),'NOT') ) head(DEG)## logFC logCPM LR PValue FDR ## hsa-mir-508 -4.264945 5.3610815 825.7952 1.329948e-181 7.341313e-179 ## hsa-mir-514-3 -4.262325 3.5005425 674.3829 1.112883e-148 3.071556e-146 ## hsa-mir-514-2 -4.258203 3.4771070 658.6855 2.885406e-145 5.309148e-143 ## hsa-mir-506 -5.522829 0.7477531 654.6812 2.143124e-144 2.957511e-142 ## hsa-mir-514-1 -4.271951 3.4852217 642.0128 1.219493e-141 1.346320e-139 ## hsa-mir-514b -5.956182 0.3742949 579.5893 4.606971e-128 4.238413e-126 ## change ## hsa-mir-508 DOWN ## hsa-mir-514-3 DOWN ## hsa-mir-514-2 DOWN ## hsa-mir-506 DOWN ## hsa-mir-514-1 DOWN ## hsa-mir-514b DOWNtable(DEG$change)## ## DOWN NOT UP ## 64 368 120edgeR_DEG <- DEG

3.limma-voom

library(limma)


design <- model.matrix(~0+group_list)

colnames(design)=levels(group_list)

rownames(design)=colnames(expr)
dge <- DGEList(counts=expr)

dge <- calcNormFactors(dge)

logCPM <- cpm(dge, log=TRUE, prior.count=3)
v <- voom(dge,design, normalize="quantile")

fit <- lmFit(v, design)
constrasts = paste(rev(levels(group_list)),collapse = "-")

cont.matrix <- makeContrasts(contrasts=constrasts,levels = design) 

fit2=contrasts.fit(fit,cont.matrix)

fit2=eBayes(fit2)

DEG = topTable(fit2, coef=constrasts, n=Inf) DEG = na.omit(DEG) #logFC_cutoff <- with(DEG,mean(abs(logFC)) + 2*sd(abs(logFC)) ) logFC_cutoff <- 1 DEG$change = as.factor( ifelse(DEG$P.Value < 0.05 & abs(DEG$logFC) > logFC_cutoff, ifelse(DEG$logFC > logFC_cutoff ,'UP','DOWN'),'NOT') ) head(DEG)## logFC AveExpr t P.Value adj.P.Val ## hsa-mir-141 -5.492612 2.990323 -31.22459 1.280624e-127 7.069043e-125 ## hsa-mir-200c -5.333666 5.687063 -30.87441 8.224995e-126 2.270099e-123 ## hsa-mir-3613 2.199074 3.862900 23.32209 5.152888e-86 9.481314e-84 ## hsa-mir-15a 1.335460 7.014647 22.83389 2.008313e-83 2.771472e-81 ## hsa-mir-934 -3.234590 -1.930201 -22.39709 4.148098e-81 4.579500e-79 ## hsa-mir-122 5.554068 3.112250 22.33183 9.192713e-81 8.457296e-79 ## B change ## hsa-mir-141 280.9396 DOWN ## hsa-mir-200c 276.7881 DOWN ## hsa-mir-3613 185.4023 UP ## hsa-mir-15a 179.4222 UP ## hsa-mir-934 174.1455 DOWN ## hsa-mir-122 173.3486 UPlimma_voom_DEG <- DEG #save(DESeq2_DEG,edgeR_DEG,limma_voom_DEG,group_list,file = "DEG.Rdata")

4.差异分析结果的可视化

#作图函数是我自己写的，在3-plotfunction.R里，在示例数据中提供了，需放在工作目录下。rm(list = ls()) load("tcga_kirc_exp.Rdata") load("DEG.Rdata") source("3-plotfunction.R") logFC_cutoff <- 1 expr[1:4,1:4]## TCGA-A3-3307-01A-01T-0860-13 TCGA-A3-3308-01A-02R-1324-13 ## hsa-let-7a-1 5056 14503 ## hsa-let-7a-2 10323 29238 ## hsa-let-7a-3 5429 14738 ## hsa-let-7b 17908 37062 ## TCGA-A3-3311-01A-02R-1324-13 TCGA-A3-3313-01A-02R-1324-13 ## hsa-let-7a-1 8147 7138 ## hsa-let-7a-2 16325 14356 ## hsa-let-7a-3 8249 7002 ## hsa-let-7b 28984 6909dat = log(expr+1) pca.plot = draw_pca(dat,group_list)


cg1 = rownames(DESeq2_DEG)[DESeq2_DEG$change !="NOT"]

cg2 = rownames(edgeR_DEG)[edgeR_DEG$change !="NOT"]

cg3 = rownames(limma_voom_DEG)[limma_voom_DEG$change !="NOT"]

h1 = draw_heatmap(expr[cg1,],group_list) h2 = draw_heatmap(expr[cg2,],group_list) h3 = draw_heatmap(expr[cg3,],group_list)v1 = draw_volcano(test = DESeq2_DEG[,c(2,5,7)],pkg = 1) v2 = draw_volcano(test = edgeR_DEG[,c(1,4,6)],pkg = 2) v3 = draw_volcano(test = limma_voom_DEG[,c(1,4,7)],pkg = 3) ##　点评：　这个　拼图语法很棒，通俗易懂 library(patchwork) (h1 + h2 + h3) / (v1 + v2 + v3) +plot_layout(guides = 'collect')

#(v1 + v2 + v3) +plot_layout(guides = 'collect') ggsave("heat_volcano.png",width = 21,height = 9)

5.三大R包差异基因对比

# 三大R包差异基因交集 UP=function(df){ rownames(df)[df$change=="UP"] } DOWN=function(df){ rownames(df)[df$change=="DOWN"] }


up = intersect(intersect(UP(DESeq2_DEG),UP(edgeR_DEG)),UP(limma_voom_DEG))

down = intersect(intersect(DOWN(DESeq2_DEG),DOWN(edgeR_DEG)),DOWN(limma_voom_DEG))
hp = draw_heatmap(expr[c(up,down),],group_list)
#上调、下调基因分别画维恩图

up.plot <- venn(UP(DESeq2_DEG),UP(edgeR_DEG),UP(limma_voom_DEG), "UPgene" )down.plot <- venn(DOWN(DESeq2_DEG),DOWN(edgeR_DEG),DOWN(limma_voom_DEG), "DOWNgene" ) #维恩图拼图，终于搞定

library(cowplot) library(ggplotify) up.plot = as.ggplot(as_grob(up.plot)) down.plot = as.ggplot(as_grob(down.plot)) library(patchwork) #up.plot + down.plot# 就爱玩拼图 pca.plot + hp+up.plot +down.plotggsave("deg.png",height = 10,width = 10)