ECON 1 Lecture Notes - Lecture 14: Positron Emission Tomography, Oncogene, Signal Transduction
Document Summary
Chromosomal aberrations: in metaphase, interphase cells translocations, aneusomies, deletions, amplifications. Unlike diseases such as cystic fibrosis or down syndrome, wherein mutations in one gene or chromosome aneusomy can cause a disease or syndrome, no single gene defect causes" cancer. But initiation could start with a single mutation. Only when several genes are defective or deregulated an invasive cancer develop. Thus it is best to think of mutated cancer genes as contributing to, rather than causing, cancer. Alterations in three types of genes are important for tumorigenesis: oncogenes, tumor-suppressor genes and stability genes. The hit: most cancers derive from a single abnormal cell with an initial mutation (monoclonal origin). Female: one of the x chromosomes is inactivated. A random process during embryonic development and during life time retained. Tumour originate from a single cell (proof: maternal or paternal x-chromosome inactivated). Additional hits: tumor becomes immortal, invasive and metastatic. Spontaneous mutation (10-6 mutations per gene per cell)
