chapter 9 Flashcards
what is neoplasia
neoplasia is a tumor, its any abnormal proliferation of cells, benign or malignant
what are the characteristics of benign tumors
the cells in the tumor resemble cells of origin, they cells tend to grow slowly and are encapsulated within well defined areas, do not have the potential to kill but can be dangerous depending on location of the tumor
malignant cancerous tumors
malignant cancerous tumors have a high degree of anaplasia do not resemble the original cell, they can no longer divide and differentiate normally, can divide without control very quickly and can metastazise
what is Anaplasia
Anaplasia is a loss of differentiation, they no longer demonstrate the appearance and function of the original cell
what are the 8 properties of Cancer cells
don’t display contact inhibition, don’t require growth factors or they produce their own, less stringent in their interactions, cancer cells generally secrete enzyme proteases that digest extracellular matrix that allows them to escape, angiogenesis, Anaplasia, cancer cells do not undergo apoptosis, and can produce enzyme telomerase to protect their telomeres
3 steps in development of cancer
initiation to promotion to progression
what leads to initiation
DNA damage leads to mutation and initiation
what leads to promotion
proliferation leads to promotion
what leads to the progression of cancer
development of cancerous phenotypes leads to progression
what leads to initiation
initiation occurs when the cell is exposed to an initiating substance or events that damage DNA that occurs in genes that control cell division leading to mutations
oncogenes
oncogenes are mutated or abnormally expressed versions of proto-oncogenes which are normal genes that regulate cell growth and division
what happens when proto-oncogenes become oncogenes
they can promote uncontrolled cell proliferating which contributes to the development of cancer
characteristics of oncogenes
gain of function mutations, oncogenes result from mutations that enhance the activity of the protein or cause it to be expressed inappropriately, only one allele of the proto-oncogene needs to be mutated for it to become an oncogene
carcinogens
factors that damage DNA, examples of carcinogens are ROS, UV light exposure, radiation, chemical exposure
what are protooncogenes
protooncogenes are genes that code for normal proteins involved in the control of cell division and differentiation (cyclins, CDKs, PK, receptors, Ras
what are tumor suppressor genes
tumor suppressor genes are represent the opposite of cell growth, acting to inhibit cell proliferation and tumor development: tumor suppressor genes are normal genes that code for proteins involved in control and slowing down cell division, repairing DNA mistakes and inducing apoptosis
what does a turned off tumor supressor gene mean
you have a cancerous cell, they only contribute to cancer when they are not lost or turned off both copies of a tumor suppressor gene in a chromosome must be mutated to develop cancer
Rb tumor supressor gene
DNA replication, cell division and death, prevents passage of cells from G1 to S prevents cells from replicating when DNA is damaged
p53 tumor supressor
apoptosis, p53 activates DNA repair enzymes when DNA is damaged and inhibits completion of the cell cycle when DNA is damaged, it hold the cell in G1-S point to allow for DNA repair
what is the most common mutation in cancer
mutated p53 gene
Braca 1&2 tumor supressor genes
cell division and death, repair of double stranded DNA breaks
APC
DNA damage, cell division, migration, adhesion, death In colon cancer, APC protein controls involved in cell adhesion in development of colon polyps A polyp in the gut lining, caused by loss of the APC gene, can progress to cancer by accumulation of further mutations (Ras and p53)
tumor staging
tumor staging is the indication of the spread, how much the tumor as metastisized
tumor grading
grading is used to describe what your tumor looks like under a microscope to get an idea of the progression, this refers to the degree of anaplasia or cell differentiation, graded 1-4 based on severity high grade tumors grade 4 are poorly differentiated have greater anaplasia and are more aggressive than low grade ones
