groupComparisonTMT {MSstatsTMT} | R Documentation

## Finding differentially abundant proteins across conditions in TMT experiment

### Description

Tests for significant changes in protein abundance across conditions based on a family of linear mixed-effects models in TMT experiment. Experimental design of case-control study (patients are not repeatedly measured) is automatically determined based on proper statistical model.

### Usage

    groupComparisonTMT(
      data,
      contrast.matrix = "pairwise",
      moderated = FALSE,
      adj.method = "BH"
    )

### Arguments

`data` | Name of the output of `proteinSummarization` function. It should have columns named Protein, Mixture, TechRepMixture, Run, Channel, Condition, BioReplicate, Abundance.
`contrast.matrix` | Comparison between conditions of interests. 1) default is 'pairwise', which compare all possible pairs between two conditions. 2) Otherwise, users can specify the comparisons of interest. Based on the levels of conditions, specify 1 or -1 to the conditions of interests and 0 otherwise. The levels of conditions are sorted alphabetically.
`moderated` | TRUE will moderate t statistic; FALSE (default) uses ordinary t statistic.
`adj.method` | adjusted method for multiple comparison. "BH" is default.

### Value

data.frame with result of inference

### Examples

    data(input.pd)
    # use protein.summarization() to get protein abundance data
    quant.pd.msstats <- proteinSummarization(input.pd,
                                           method="msstats",
                                           global_norm=TRUE,
                                           reference_norm=TRUE)

    test.pairwise <- groupComparisonTMT(quant.pd.msstats, moderated = TRUE)

    # Only compare condition 0.125 and 1
    levels(quant.pd.msstats$Condition)

    # Compare condition 1 and 0.125
    comparison<-matrix(c(-1,0,0,1),nrow=1)

    # Set the names of each row
    row.names(comparison)<-"1-0.125"

    # Set the column names
    colnames(comparison)<- c("0.125", "0.5", "0.667", "1")
    test.contrast <- groupComparisonTMT(data = quant.pd.msstats,
    contrast.matrix = comparison,
    moderated = TRUE)

[Package MSstatsTMT version 1.4.6 Index]