Study shows how melanomas assist T cells from identifying and killing tumor cells Cancers like melanoma are hard to treat, not least because they have a varied bag of tricks for defeating or evading treatments. Now, a combined research effort by the Weizmann Institute of Science, the Netherlands Cancer Institute in Amsterdam, and the University of Oslo shows exactly how tumors, in their fight to survive, will go so far as to starve themselves in order to keep the immune cells that would eradicate them from functioning. The work was published in Nature. The immunotherapies currently administered for melanomas work by removing obstacles that keep immune cells called T cells from identifying and killing tumor cells. Recent research suggested that, in melanoma, another blocker – one that stops IDO1, an enzyme that is overproduced by cancer cells – could also assist the T cells.