JNK inhibitor peptide consisting of an amino acid sequence according to SEQ ID NO: 2 or chimeric peptide consisting of a first domain and a second domain linked by a covalent bond, the first domain comprising a traffic sequence and the second domain consisting in a JNK inhibitory sequence according to SEQ ID NO: 2, for use in a method of treating cancerous diseases selected from Kaposi's sarcoma, acute myeloid leukemia, including erythroleukemia, melanomas, malignant melanomas, colon carcinomas, lymphomas, sarcomas, blastomas, renal carcinomas, gastrointestinal tumors, gliomas, prostate tumors, bladder cancer, rectal tumors, stomach cancer, esophageal cancer, pancreatic cancer, liver cancer, breast carcinomas (>; = breast cancer), cancer of the uterus, cervical cancer, acute myeloid leukemia (AML), acute lymphoid leukemia (ALL), chronic myeloid leukemia (CML), leukem Chronic lymphocytic (CLL), hepatomas, various virus-induced tumors, such as papilloma, virus-induced carcinomas (for example cervical carcinoma>; = cervical cancer), adenocarcinomas, herpes virus-induced tumors (for example Burkitt lymphoma, B-cell-induced EBV lymphoma), hepatitis B-induced tumors (hepatocellular carcinomas), HTLV-1 and HTLV-2-induced lymphomas, acoustic neuroma, lung carcinomas (>; = lung cancer>; = bronchial carcinoma), lung carcinomas small cells, throat cancer, anal carcinoma, glioblastoma, rectal carcinoma, astrocytoma, brain tumors, retinoblastoma, basalioma, brain metastases, medulloblastomas, vaginal cancer, testicular cancer, thyroid carcinoma, Hodgkin's syndrome, meningeomas, Schneeberger's disease, tumors of the pituitary, mycosis fungoides, carcinoids, neurinoma, spinalioma, Burkitt lymphoma, laryngeal cancer, kidney cancer, thymoma, carcin oma corpus, bone cancer, non-Hodgkin lymphomas, urethral cancer, CUP syndrome, head / neck tumors, oligodendroglioma, vulval cancer, intestinal cancer, colon carcinoma, esophageal carcinoma (>; = esophageal cancer), warts, bowel