The past 6 years since the first edition of this book have seen great progress in the development of genetically engineered mouse (GEM) models of cancer. These models are finding an important role in furthering our understanding of the biology of malignant disease. A comfortable position for GEM models in the routine conduct of screening for potential new therapeutics is coming more slowly but is coming. Increasing numbers of genetically engineered mice are available, some with conditional activation of oncogenes, some with multiple genetic changes providing mouse models that are moving closer to the human disease.

Experienced cancer researchers from pharmaceutical companies, government laboratories, and academia comprehensively review and describe the arduous process of cancer drug discovery and approval. They focus on using preclinical in vivo and in vitro methods to identify molecules of interest, detailing the targets and criteria for success in each type of testing and defining the value of the information obtained from the various tests. They also define each stage of clinical testing, explain the criteria for success, and outline the requirements for FDA approval. A companion volume by the same editor (Cancer Therapeutics: Experimental and Clinical Agents) reviews existing anticancer drugs and potential anticancer therapies. These two volumes in the Cancer Drug Discovery and Development series reveal how and why molecules become anticancer drugs and thus offer a blueprint for the present and the future of the field.

The past 6 years since the first edition of this book have seen great progress in the development of genetically engineered mouse (GEM) models of cancer. These models are finding an important role in furthering our understanding of the biology of malignant disease. A comfortable position for GEM models in the routine conduct of screening for potential new therapeutics is coming more slowly but is coming. Increasing numbers of genetically engineered mice are available, some with conditional activation of oncogenes, some with multiple genetic changes providing mouse models that are moving closer to the human disease.

Cancer drug discovery has been and continues to be a process of ingenuity, serendip ity, and dogged determination. In an effort to develop and discover better therapies against cancer, investigators all over the world have increased our knowledge of cell biology, biochemistry, and molecular biology. The goal has been to define therapeuti cally exploitable differences between normal and malignant cells. The result has been an increased understanding of cellular and whole-organism biology and an increased respect for the flexibility and resiliency ofbiologically systems. Thus, as some new therapeutic targets have been defined and new therapeutic strategies have been attempted, so have some new biological hurdles resulting from tumor evasion of the intended therapeutic attack been discovered. Historically, anticancer drugs have originated from all available chemical sources. Synthetic molecules from the chemical industry, especially dyestuffs and warfare agents, and natural products from plants, microbes, and fungi have all been potential sources of pharmaceuticals, including anticancer agents. There is no shortage of molecules; the challenge has been and continues to be methods of identifying molecules that have the potential to be therapeutically important in human malignant disease. "Screening" remains the most important and most controversial method in cancer drug discovery. In vitro screens have generally focused on cytotoxicity and have identified several highly cytotoxic molecules. Other endpoints available in vitro are inhibition of proliferation, 3 inhibition of [ H]thymidine incorporation into DNA and various viability assays, based most frequently on dye exclusion or metabolism.

Leading experts summarize and synthesize the latest discoveries concerning the changes that occur in tumor cells as they develop resistance to anticancer drugs, and suggest new approaches to preventing and overcoming it. The authors review physiological resistance based upon tumor architecture, cellular resistance based on drug transport, epigenetic changes that neutralize or bypass drug cytotoxicity, and genetic changes that alter drug target molecules by decreasing or eliminating drug binding and efficacy. Highlights include new insights into resistance to antiangiogenic therapies, oncogenes and tumor suppressor genes in therapeutic resistance, cancer stem cells, and the development of more effective therapies. There are also new findings on tumor immune escape mechanisms, gene amplification in drug resistance, the molecular determinants of multidrug resistance, and resistance to taxanes and Herceptin.

This unique volume traces the critically important pathway by which a "molecule" becomes an "anticancer agent. " The recognition following World War I that the administration of toxic chemicals such as nitrogen mustards in a controlled manner could shrink malignant tumor masses for relatively substantial periods of time gave great impetus to the search for molecules that would be lethal to specific cancer cells. Weare still actively engaged in that search today. The question is how to discover these "anticancer" molecules. Anticancer Drug Development Guide: Preclinical Screening, Clinical Trials, and Approval, Second Edition describes the evolution to the present of preclinical screening methods. The National Cancer Institute's high-throughput, in vitro disease-specific screen with 60 or more human tumor cell lines is used to search for molecules with novel mechanisms of action or activity against specific phenotypes. The Human Tumor Colony-Forming Assay (HTCA) uses fresh tumor biopsies as sources of cells that more nearly resemble the human disease. There is no doubt that the greatest successes of traditional chemotherapy have been in the leukemias and lymphomas. Since the earliest widely used in vivo drug screening models were the murine L 1210 and P388 leukemias, the community came to assume that these murine tumor models were appropriate to the discovery of "antileukemia" agents, but that other tumor models would be needed to discover drugs active against solid tumors.

Cancer drug discovery has been and continues to be a process of ingenuity, serendip ity, and dogged determination. In an effort to develop and discover better therapies against cancer, investigators all over the world have increased our knowledge of cell biology, biochemistry, and molecular biology. The goal has been to define therapeuti cally exploitable differences between normal and malignant cells. The result has been an increased understanding of cellular and whole-organism biology and an increased respect for the flexibility and resiliency ofbiologically systems. Thus, as some new therapeutic targets have been defined and new therapeutic strategies have been attempted, so have some new biological hurdles resulting from tumor evasion of the intended therapeutic attack been discovered. Historically, anticancer drugs have originated from all available chemical sources. Synthetic molecules from the chemical industry, especially dyestuffs and warfare agents, and natural products from plants, microbes, and fungi have all been potential sources of pharmaceuticals, including anticancer agents. There is no shortage of molecules; the challenge has been and continues to be methods of identifying molecules that have the potential to be therapeutically important in human malignant disease. "Screening" remains the most important and most controversial method in cancer drug discovery. In vitro screens have generally focused on cytotoxicity and have identified several highly cytotoxic molecules. Other endpoints available in vitro are inhibition of proliferation, 3 inhibition of [ H]thymidine incorporation into DNA and various viability assays, based most frequently on dye exclusion or metabolism.

This volume represents a compendium of scientific findings and approaches to the study of angiogenesis in cancer. The second edition of Antiangiogenic Agents in Cancer Therapy is intended to give a current perspective on the state-of-the-art of angiogenensis and therapy directed at this process. Antiangiogenesis is a dynamic and evolving field in oncology. New therapeutic targets continue to emerge followed by the rapid development of new therapeutic agents to be investigated in clinical trials. Optimizing the therapeutic potential of antiangiogenic agents in combination with the other therapies in the armamentarium to fight cancer will be an on-going challenge.

This unique volume traces the critically important pathway by which a "molecule" becomes an "anticancer agent. " The recognition following World War I that the administration of toxic chemicals such as nitrogen mustards in a controlled manner could shrink malignant tumor masses for relatively substantial periods of time gave great impetus to the search for molecules that would be lethal to specific cancer cells. Weare still actively engaged in that search today. The question is how to discover these "anticancer" molecules. Anticancer Drug Development Guide: Preclinical Screening, Clinical Trials, and Approval, Second Edition describes the evolution to the present of preclinical screening methods. The National Cancer Institute's high-throughput, in vitro disease-specific screen with 60 or more human tumor cell lines is used to search for molecules with novel mechanisms of action or activity against specific phenotypes. The Human Tumor Colony-Forming Assay (HTCA) uses fresh tumor biopsies as sources of cells that more nearly resemble the human disease. There is no doubt that the greatest successes of traditional chemotherapy have been in the leukemias and lymphomas. Since the earliest widely used in vivo drug screening models were the murine L 1210 and P388 leukemias, the community came to assume that these murine tumor models were appropriate to the discovery of "antileukemia" agents, but that other tumor models would be needed to discover drugs active against solid tumors.