The PTP inhibitor sodium stibogluconate (SSG), a drug used in the treatment of leishmaniasis [152] and identified as an inhibitor of both SHP-1 and SHP-2 [153], increases interferon-α (IFN-α)-induced signal transducer and activator of transcription 1 (STAT1) tyrosine phosphorylation and has been shown to synergize with IFN-α to inhibit WM9 human melanoma tumor growth in nude mice [154]. Here, PTPN6 is linked to melanoma.