It is mainly expressed intracellularly and the protein has nine different isoforms, because the pre-mRNA can be alternatively spliced.

[5] mRNA of IL-32 is mostly expressed in immune cells but also can be expressed in other tissues such as spleen, thymus, lung, small intestine, colon, prostate, heart, placenta, liver, muscle, kidney, pancreas and brain.

Alternate transcriptional splice variants, encoding different isoforms, have been characterized.

IL-32 supports the tumor progression by cytokines expressed after activation of transcription factor NF-κB (nuclear factor-kB) and by metalloproteinase production.

[10] This article incorporates text from the United States National Library of Medicine, which is in the public domain.