Transcription factor involved in monocyte-to-macrophage differentiation. Forms a complex with NPM1 to translocate to the nucleus, acting as a transcription factor that promotes the expression of the genes involved in macrophage differentiation, such as STAT3, STAT1 and JUNB. . This is the function of ARID3C (AT-rich interaction domain 3C, Ensembl gene identifier ENSG00000205143).