emba (version 0.1.1)

biomarker_synergy_analysis: Biomarker analysis per synergy predicted

Description

Use this function to discover synergy biomarkers, i.e. nodes whose activity and/or boolean equation parameterization (link operator) affect the manifestation of synergies in the models. Models are classified based on whether they predict or not each of the predicted synergies.

Usage

biomarker_synergy_analysis(model.predictions, models.stable.state,
  models.link.operator = NULL, observed.synergies, threshold)

Arguments

model.predictions

a data.frame object with rows the models and columns the drug combinations. Possible values for each model-drug combination element are either 0 (no synergy predicted), 1 (synergy was predicted) or NA (couldn't find stable states in either the drug combination inhibited model or in any of the two single-drug inhibited models).

models.stable.state

a matrix (nxm) with n models and m nodes. The row names of the matrix specify the models' names whereas the column names specify the name of the network nodes (gene, proteins, etc.). Possible values for each model-node element are either 0 (inactive node) or 1 (active node). Note that the rows (models) have to be in the same order as in the model.predictions parameter.

models.link.operator

a matrix (nxm) with n models and m nodes. The row names of the matrix specify the models' names whereas the column names specify the name of the network nodes (gene, proteins, etc.). Possible values for each model-node element are either 0 (AND NOT link operator), 1 (OR NOT link operator) or 0.5 if the node is not targeted by both activating and inhibiting regulators (no link operator). Default value: NULL (no analysis on the models parameterization regarding the mutation of the boolean equation link operator will be done).

observed.synergies

a character vector with elements the names of the drug combinations that were found as synergistic. This should be a subset of the tested drug combinations, that is the column names of the model.predictions parameter.

threshold

numeric. A number in the [0,1] interval, above which (or below its negative value) a biomarker will be registered in the returned result. Values closer to 1 translate to a more strict threshold and thus less biomarkers are found.

Value

a list with various elements:

  • observed.model.predictions: the part of the model.predictions data that includes the observed.synergies.

  • unobserved.model.predictions: the complementary part of the model.predictions data that does not include the observed.synergies

  • predicted.synergies: a character vector of the synergies (drug combination names) that were predicted by at least one of the models in the dataset.

  • synergy.subset.stats: an integer vector with elements the number of models the predicted each observed synergy subset.

  • diff.state.synergies.mat: a matrix whose rows are vectors of average node activity state differences between two groups of models where the classification for each individual row was based on the prediction or not of a specific synergistic drug combination. The row names are the predicted synergies, one per row, while the columns represent the network's node names. Values are in the [-1,1] interval.

  • activity.biomarkers: a data.frame object with rows the predicted synergies and columns the nodes (column names of the models.stable.states matrix). Possible values for each synergy-node element are either 1 (active state biomarker), -1 (inhibited state biomarker) or 0 (not a biomarker) for the given threshold value.

  • diff.link.synergies.mat: a matrix whose rows are vectors of average node link operator differences between two groups of models where the classification for each individual row was based on the prediction or not of a specific synergistic drug combination. The row names are the predicted synergies, one per row, while the columns represent the network's node names. Values are in the [-1,1] interval.

  • link.operator.biomarkers: a data.frame object with rows the predicted synergies and columns the nodes (column names of the models.link.operator matrix). Possible values for each synergy-node element are either 1 (OR link operator biomarker), -1 (AND link operator biomarker) or 0 (not a biomarker) for the given threshold value.

See Also

Other general analysis functions: biomarker_mcc_analysis, biomarker_tp_analysis