BIO 325 Chapter Notes - Chapter 19-20: E2F, Gene Pool, Centromere
Document Summary
Immune surveillance: process by which the human immune system recognizes and attacks foreign bodies. Ca(cid:374)(cid:272)e(cid:396) (cid:272)ells do(cid:374)"t (cid:396)espo(cid:374)d to the sa(cid:373)e (cid:272)o(cid:374)t(cid:396)ols that li(cid:373)it (cid:374)o(cid:396)(cid:373)al (cid:272)ell di(cid:448)isio(cid:374), su(cid:272)h as (cid:272)o(cid:374)ta(cid:272)t inhibition, apoptosis signals, or the absence of growth factors. Many cancer cells can divide indefinitely due to telomerase expression. Many cancer cells have high genomic instability, which leads to large accumulations of mutations and chromosomal abnormalities. Advanced tumors can stimulate local blood vessel growth, which help it to e(cid:448)ade the (cid:271)ody"s normal immune defenses and eventually metastasize to other tissues. Cancers are the results of accumulation of mutations in certain critical genes in a mitotically dividing clone of somatic cells. Support for this model of cancer genesis come from observations of cancer rates increasing after exposure to mutagens, the patient simply aging, and from rare inherited mutagens. Increased cell proliferation leads to genomic instability, which resulting in mutations, which leads to more proliferation, and acquisition of additional cancer-promoting properties.
