Profiling Tumor Infiltrating Immune Cells with CIBERSORT

Methods Mol Biol. 2018:1711:243-259. doi: 10.1007/978-1-4939-7493-1_12.

Abstract

Tumor infiltrating leukocytes (TILs) are an integral component of the tumor microenvironment and have been found to correlate with prognosis and response to therapy. Methods to enumerate immune subsets such as immunohistochemistry or flow cytometry suffer from limitations in phenotypic markers and can be challenging to practically implement and standardize. An alternative approach is to acquire aggregative high dimensional data from cellular mixtures and to subsequently infer the cellular components computationally. We recently described CIBERSORT, a versatile computational method for quantifying cell fractions from bulk tissue gene expression profiles (GEPs). Combining support vector regression with prior knowledge of expression profiles from purified leukocyte subsets, CIBERSORT can accurately estimate the immune composition of a tumor biopsy. In this chapter, we provide a primer on the CIBERSORT method and illustrate its use for characterizing TILs in tumor samples profiled by microarray or RNA-Seq.

Keywords: Cancer immunology; Deconvolution; Gene expression; Microarray; RNA-Seq; Support vector regression (SVR); TCGA; Tumor heterogeneity; Tumor infiltrating leukocytes (TILs); Tumor microenvironment.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Gene Expression Profiling / methods*
  • Gene Expression Regulation, Neoplastic
  • Genomics / methods*
  • Humans
  • Lymphocytes, Tumor-Infiltrating / metabolism*
  • Lymphocytes, Tumor-Infiltrating / pathology
  • Neoplasms / genetics*
  • Neoplasms / pathology
  • Software*
  • Support Vector Machine
  • Transcriptome
  • Tumor Microenvironment*