get_new_samp_score {ssPATHS} | R Documentation

## Get a pathway score for an unseen sample

### Description

Using the gene weights learned from the reference cohort, we apply the weightings to new samples to estimate their pathway activity.

### Usage

    get_new_samp_score(gene_weights, expression_se, gene_ids, run_normalization = TRUE)

### Arguments

`gene_weights` | This is a data.frame containing gene ids and gene weights, output by get_gene_weights. The gene ids must be in the column ids of expression_matr.
`expression_se` | This is an SummarizedExperiment object of the reference samples. Rows are genes and columns are samples. The colData component must contain columns `Y` and `sample_id`. The former indicates whether this is a positive or negative sample and the latter is the unique sample id. Within this method, there is a normalization step where each sample is scaled across all genes in the SummarizedExperiment assay. For this to be stable and consistent, we recommend that the assay contain at least 500 genes that are consistently expressed across all samples in addition to the genes in the pathway of interest.
`gene_ids` | This is a vector of strings, where each element is a `gene_id` in the pathway of interest. The `gene_id`s must be present in `rownames(expression_se)`.
`run_normalization` | Boolean value. If TRUE, the data will be log-transformed, centered and scaled. This is recommended since this is done to the reference set when learning the gene weights.

### Value

A data.frame containing the sample id, sample score, and associated Y value if it was included in expression_se.

### Author(s)

Natalie R. Davidson

### Examples

    data(tcga_expr_df)

    # transform from data.frame to SummarizedExperiment
    tcga_se <- SummarizedExperiment(t(tcga_expr_df[ , -(1:4)]),
                                    colData=tcga_expr_df[ , 2:4])
    colnames(tcga_se) <- tcga_expr_df$tcga_id
    colData(tcga_se)$sample_id <- tcga_expr_df$tcga_id

    # get the genes of interest, here hypoxia genes
    hypoxia_gene_ids <- get_hypoxia_genes()
    hypoxia_gene_ids <- intersect(hypoxia_gene_ids, rownames(tcga_se))

    # label the samples for classification
    colData(tcga_se)$Y <- ifelse(colData(tcga_se)$is_normal, 0, 1)

    # now we can get the gene weightings
    res <- get_gene_weights(tcga_se, hypoxia_gene_ids, unidirectional=TRUE)
    gene_weights <- res[[1]]
    sample_scores <- res[[2]]

    # get the new data so we can apply our score to it
    data(new_samp_df)
    new_samp_se <- SummarizedExperiment(t(new_samp_df[ , -(1)]),
                                        colData=new_samp_df[ , 1, drop=FALSE])
    colnames(colData(new_samp_se)) <- "sample_id"

    new_score_df_calculated <- get_new_samp_score(gene_weights, new_samp_se)

[Package ssPATHS version 1.8.0 Index]