NN+19.1+Notes

Cancer Notes (19.1)
QUESTIONS:
 * 1) What characteristics of cancer cells allow them to grow uncontrollably? **Cancer cells are mutated cells that are able to reproduce even after they have reached their neighboring cells. A cancer cell has certain genes mutated that inhibit apoptosis. The unavailability of p53 and other apoptosis promoting proteins allows the cell to continue to reproduce without dying.**
 * 2) Mutations in what two types of genes led to uncontrollable growth? **The two cells that mutate are Proto-oncogenes and Tumor-suppressing genes. Proto-oncogenes are genes that code for proteins to promote cell division and prevent apoptosis. Tumor-suppressing genes code for proteins that stop the cell dividing process and encourage apoptosis.**
 * 3) What are the most common types of cancer? **Men are more prone to develop prostate cancer, bladder cancers, and kidney cancers. Women are more prone to develop cervical cancer, and breast cancer. Other common cancers include: lung cancer, leukemia, thyroid cancer, brain cancer, and spinal cancers.**

A. Characteristics of Cancer B. Cancer Cells and Tumors C. Cancer is a Genetic Disease D. Types of Cancer
 * Cancer cells are abnormal and do not contribute to the human body
 * Cancer cells have enlarged nuclei that take up most of the cell
 * Chromosomes of cancerous cells are abnormal, and either have duplicated or deleted chromosomes
 * **A****poptosis**: programmed cell death (a process that normal cells undergo when they are corrupted, but cancerous cells do not
 * Tissues that divide often are more likely to become cancerous
 * Most cells divide 60-70 times and then die, but cancerous cells can divide an unlimited number of times and never die
 * **Telomeres**:special repetitive DNA sequences (get shorter after each cell cycle, until so small chromosomes bind and the cell undergoes apoptosis)
 * The gene that codes for Telomerase is turned on in cancer cells
 * when normal cells come in contact with their neighboring cells, they stop, but when a cancerous cell meets its neighbor, it continues to duplicate, and forms a tumor
 * the three stages of carginogenesis (development of cancer)
 * initiation: one cell is mutated and begins to divide repeatedly
 * promotion: a tumor is developed, and the cells continue to divide. the cells also continue to undergo mutations
 * progression: one cell undergoes mutations and gets an advantage over the other cells, several cells then go under mutations, and continue to mutate until there is a cell that can invade other tissues
 * **Angiogenesis:** the formation of new blood vessels
 * with the low oxygen levels in tumors, the genes coded for angiogenesis start working and new blood vessels are formed
 * **Metastasis:** when cells begin new tumors far from the primary tumor
 * few cancer cells achieve metastasis (1 in 10,000)
 * to achieve metastasis, the cells have to get through the basement membrane and invade a blood vessel or a lymphatic vessel
 * for cell reproduction, the cyclin molecule is required for cells to go into interphase
 * cancers repeated divisions is due largely to the mutation of two types of genes
 * **Proto-oncogenes**: codes for proteins that promote cell division and prevents apoptosis.
 * when they mutate, they are called oncogenes. "whatever a proto-oncongene does, an oncongene does it better"
 * **Tumor-Suppressor genes:** code for the proteins that inhibits cell division, and promotes apoptosis
 * **p53**: a protein that activates the genes that stop cell division and promotes apoptosis.
 * in a tumor, p53 is unavailable to encourage the cells to stop dividing
 * **Bax**: promotes apoptasis
 * when a tumor-suppressor gene Bax mutates, Bax is not present, making apoptosis less likely to occur
 * has 8 G bases
 * **Oncology**: the study of cancer
 * CARCINOMAS: cancers of the epithelial tissues and adenocarcinomas. includes skin, breast, liver, pancreas, intestines, lung, prostate, and thyroid cancers
 * SARCOMAS: cancers that are found in muscles and connective tissues. includes bone and fibrous connective tissue cancers
 * LEUKEMIAS: cancers of the blood
 * LYMPHOMAS: cancers of lymphatic tissue