Through positive selection, double-positive cells in the thymus differentiate 
into CD4(+) or CD8(+) T single-positive cells that subsequently develop into 
different types of effective T cells, such as T-helper and cytotoxic T 
lymphocyte cells, that play distinctive roles in the immune system. Development, 
differentiation, and function of thymocytes and CD4(+) and CD8(+) T cells are 
controlled by a multitude of secreted and intracellular factors, ranging from 
cytokine signaling modules to transcription factors and epigenetic modifiers. 
Members of the E26 transformation specific (Ets) family of transcription 
factors, in particular, are potent regulators of these CD4(+) or CD8(+) T-cell 
processes. In this review, we summarize and discuss the functions and underlying 
mechanisms of the Ets family members that have been characterized as involved in 
these processes. Ongoing research of these factors is expected to identify 
practical applications for the Ets family members as novel therapeutic targets 
for inflammation-related diseases.