An experimental immunotherapy that delivers interleukin-12 (IL-12) directly into a melanoma tumor may also shrink tumors elsewhere in the body. Called ImmunoPulse, the treatment entails injecting a tumor with interleukin-12 DNA and delivering electric shocks to make the tumor cells absorb this DNA. These cells then produce IL-12, boosting the immune response against the tumor. In an ongoing phase II trial of 21 people with melanomas that were treated with ImmunoPulse, tumors shrank in 8 of them (38%) and disappeared for at least 6 months in 2 more of them. Moreover, untreated tumors also shrank in about 60%. The possibility of body-wide effects is encouraging because, in contrast to systemic IL-12 therapy, ImmunoPulse treatments have yet to cause serious side effects.