Neoplasia Flashcards
what is an oncogene
a gene whose activated product causes growth
what is a tumor suppressor gene
a gene whose product prevents growth
true or false: benign tumors are always harmless
false: benign means that the neoplasm doesn’t move other parts of bodies, can cause symptoms depending on location and size
two most common epithelial malignant neoplasms
adenocarcinoma (glands that line inside of organs) and squamous cell carcinoma (middle and outer layers of skin)
four types of malignant neoplasms
epithelium (skin), sarcoma (soft tissue), hematolymphoid (blood and lymph system), nervous system (brain and spinal cord)
two types of malignant hematolymphoid neoplasms
leukemia, lymphoma
what are the 8 hallmarks of malignant neoplasm
self-sufficiency in growth signals
insensitivity to growth inhibitors
altered cellular metabolism
evasion of apoptosis
immortality
sustained angiogenesis
ability to invade and metastasize
ability to evade human immune response
what protein is first activated by growth factor
RAS
what kind of proteins does the tumor suppressor gene activate
GAP (inactivates RAS), PTEN (inactivates PI3K)
what gene mutation can lead to breast and stomach cancers
Her2
what gene mutations can lead to lung cancers?
EGFR, ALK
what percentage of human cancers involve the growth factor, receptor, or RAS protein mutations
20%
what gene mutation leads to skin, lung, colorectal, thyroid cancers
BRAF
what does the BRAF mutation do
cause continuous production of RAF leading to cell growth
how do cancers alter cellular metabolism
more interest in reproduction than production of energy so recruit neighboring cells to switch over to anaerobic glycolysis to harvest lactate product for carbons to continue fueling anaerobic process (Warburg effect)
what actions does p53 activate
senescence (sleep), DNA repair, inhibit growth, apoptosis
what is p53
tumor suppressor gene that provides surveillance on cell’s genetic material and directs cell in how to handle genetic damage
how do malignant neoplasms avoid apoptosis and remain immortal
Tumors activate telomerase to regenerate telomeres at end of DNA stands so cell never receives signal to undergo apoptosis for damaged/mutated DNA
What are vascular stimulator genes
VEGF, bFGF
3 ways malignant neoplasms can spread
seeding of adjacent surfaces, lymphatic spread, hematogenous spread
what do MHC class I receptors signal
alerts immune system that cell is infected or broken in some way
how do tumor cells evade immune system
don’t display antigen on MHC class I receptor, stop making MHC class I receptors, make immunosuppressive (anti-inflammatory) cytokines that kill T cells
define initiation phase of carcinogen exposure
electrophilic intermediates bind to DNA and creates permanent DNA lesion
define promotion phase of carcinogen exposure
cell will replicate uncontrollably with altered DNA, ultimately leading to malignant neoplasm
how does ionizing radiation (UV and X-rays) increase risk of cancer
Waves excite electrons in our bodies causing them to cling to water. this breaks up the water molecules into free radicals which can eventually damage and break DNA
What does TNM mean when it comes to tumor staging
T: tumor (primary), how big it is
N: number of lymph nodes involved
M: metastasis, how far it traveled
