['Interleukin-32 (IL-32) is a recently recognized intracellular, proinflammatory cytokine which may play a role in cancer metastasis and patient survival. The role of IL-32 in cancer, especially its direct effect on cancer cells, is not well understood.', 'Clonogenic assay, PCNA staining, Quick Cell Proliferation assay, TUNEL staining, and caspase-3 activity assay were used to investigate the in vitro role for IL-32α in human melanoma growth. We further investigated the possible molecular mechanisms using RT-PCR and immunohistochemical staining.', 'Exogenous administration of IL-32α inhibited proliferation of the HTB-72 human melanoma cell line, but had little effect on other melanoma cell lines. Inhibition of proliferation in HTB-72 correlated with increased expression of p21 and p53. IL-32α administration also increased apoptosis in HTB-72. This finding correlated with increased expression of TRAILR1.'] Does iL-32α have differential effects on proliferation and apoptosis of human melanoma cell lines?