Table 3.

Summary of technologies used to discover biomarkers in cancer immunotherapy.

Technology	Indications
Whole exome sequencing	•Assessing mutational load for anti-CTLA-4 and anti-PD-1 therapy
	•Identifying neoantigens recognized by CD8+ T cells
Gene expression technology	•Identifying intrinsic and extrinsic immunosuppressive molecules
	•Identifying gene expression profiles
	•Optimal use of this technology involves integrating results obtained from other technologies
Epigenomics	•Assessing interaction of histone modifications and DNA methylation
	•More studies needed to validate epigenomics as a tool to identify biomarkers for immunotherapy
Proteomics	•Analyzing chemokines, cytokines, and soluble factors
	•Identifying tumor associated antigens (TAA) and their antibodies
	•Advantages include less sample volume utilized for testing, improved sensitivity and specificity, and improved high-dimensional data generation
Flow cytometry	•Analyzing phenotype and function of immune cells utilizing multiple probes
	•Limited by fluorescence spectral overlap
Mass cytometry	•Simultaneously identify multiple and more biomarkers than flow cytometry
	•Measuring immune cell phenotypes
	•Limited by slow collection speed, low recovery of cells in the instrument, and high expense
B and T cell immunosequencing	•Quantifying B and T cells with high sensitivity and reproducibility
	•Assessing TIL clonality which in turn may help to identify patients who may respond to anti-PD-1 therapy in melanoma
Multiplexed and multicolored immunohistochemistry	•Investigating sample phenotype, positivity/negativity counts and H-scoring, density measurements, and spatial point pattern analyses
	•Investigating role and function of regulatory T cells (Tregs) in anti-CTLA-4 therapy
	•Investigating density of CD8+ T cell infiltrates in melanoma patients undergoing anti-PD-1 therapy
	•Advantages include allowing for the simultaneous detection of multiple biomarkers
	•Limited by sampling size, sampling time, and expense
Radiomics	•Patients with a high radiomic score, or high CD8 score, were associated with positive treatment response and overall survival