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Harrison's Principles of Internal Medicine, 18e
| Part 7. Oncology and Hematology > Section 1. Neoplastic Disorders > |
Chapter 84. Cancer Cell Biology and Angiogenesis
Sections: Cancer Cell Biology, Epigenetic Influences on Cancer Gene Transcription, Apoptosis, Tumor Angiogenesis, Summary, Acknowledgement, Further Readings.
Topics Discussed: angiogenesis; cell biology; pathophysiology of neoplasia.
Excerpt:"Cancers are characterized by unregulated cell growth, tissue invasion, and metastasis. A neoplasm is benign when it grows in an unregulated fashion without tissue invasion. The presence of both features is characteristic of malignant neoplasms. Cancers are named based on their origin: those derived from epithelial tissue are called carcinomas, those derived from mesenchymal tissues are sarcomas, and those derived from hematopoietic tissue are leukemias or lymphomas.Normal cells have a number of control mechanisms that are targeted by specific genetic alterations in cancer. The progression of a cell through the cell division cycle is regulated at a number of checkpoints by a wide array of genes. In the first phase, G1, preparations are made to replicate the genetic material. The cell stops before entering the DNA synthesis phase or S phase to take inventory. Are we ready to replicate our DNA? Is the DNA repair machinery in place to fix any mutations that are detected? Are the DNA replicating enzymes available? Is there an adequate supply of nucleotides? Is there sufficient energy? The main brake on the process is the retinoblastoma protein, Rb. When the cell determines that it is prepared to move ahead, sequential..."
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