title: Changes in therapy for solid tumors: potential for overcoming drug resistance in vivo with molecular targeting agents.
abstract: Recent advances in molecular biology have led to the development of selective molecular targeting agents for genes involved in cell proliferation, apoptosis, and angiogenesis in cancer cells. The current success of molecular targeting therapy is shown by: imatinib mesylate (STI571, Gleevec), targeted to the Bcr/Abl fusion protein derived from a translocation between chromosomes 9 and 22 in chronic myelogenous leukemia; rituximab (Rituxan), a monoclonal antibody to CD20 used in non-Hodgkin's lymphoma; trastuzumab (Herceptin), a chimeric monoclonal antibody to HER-2 used in breast cancer; and gefinitib (ZD1839, Irresa), a tyrosine kinase inhibitor of the epidermal growth factor receptor used in non-small cell lung cancer. The superior therapeutic efficacy of these molecular targeting agents over traditional chemotherapy has been shown by the survival benefit achieved for patients with advanced or recurrent cancers. Although the precise molecular mechanisms by which these agents produce or enhance an antitumor effect, alone or in combination with anticancer drugs, are not known, the specific inhibition of target genes critically involved in tumor progression and metastasis by the agent is clear. However, further studies to determine which patient groups and anticancer drugs are appropriate for combination therapy with these molecular targeting agents are needed. Herein, we discuss the current status and potential for overcoming drug resistance in solid tumors and focus on the differential features of the tumor microenvironment in solid and hematologic malignancies.
authors.affiliation: Department of Surgical Oncology, International Radiation Information Center, Research Institute for Radiation Biology and Medicine, Hiroshima University, Japan.
authors.forename: Ryungsa
authors.initials: R
authors.lastname: Kim
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Toge
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology / Q000627:therapeutic use; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001549:Benzamides; D018450:Disease Progression; D019008:Drug Resistance, Neoplasm / Q000187:drug effects / Q000502:physiology; D016044:Fusion Proteins, bcr-abl; D000077156:Gefitinib; D006801:Humans; D000068877:Imatinib Mesylate; D008967:Molecular Biology; D009369:Neoplasms / Q000188:drug therapy* / Q000503:physiopathology; D019899:Paracrine Communication / Q000187:drug effects / Q000528:radiation effects; D010879:Piperazines / Q000494:pharmacology / Q000627:therapeutic use; D010982:Platelet-Derived Growth Factor / Q000502:physiology; D011505:Protein-Tyrosine Kinases; D011743:Pyrimidines / Q000494:pharmacology / Q000627:therapeutic use; D011799:Quinazolines / Q000494:pharmacology / Q000627:therapeutic use; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D000068878:Trastuzumab
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D001549:Benzamides; D016044:Fusion Proteins, bcr-abl; D000077156:Gefitinib; D000068877:Imatinib Mesylate; D010879:Piperazines; D010982:Platelet-Derived Growth Factor; D011505:Protein-Tyrosine Kinases; D011743:Pyrimidines; D011799:Quinazolines; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab