Robbins Neoplasia Ch 5 Flashcards
What are the hallmarks of cancer cells?
- self-sufficiency in growth signals
- lack of response to growth inhibitory signals
- evasion of cell death
- limitless replicative potential
- development of angiogenesis to sustain growth
- ability to invade local tissues and spread
- reprogramming of metabolic pathways, specifically a switch to aerobic glycolysis
- ability to evade the immune system
What are the two basic componenets of tumors?
the parenchyma - transformed neoplastic cells
AND
the stroma - non-neoplastic supporting cells derived from the host (connective tissue, blood vessels, host inflammatory cells)
What is a chondroma?
benign tumor begininning in cartilage
Where do papillomas begin?
epithelium. They develop finger-like projections.
What are cystadenomas?
hollow cystic masses that typically arise in the ovary
What are neoplasms arising from mesenchymal tissues called?
sarcomas
What are leukemias?
neoplasms arising from blood
What is a fibrosarcoma?
a cancer of fibrou stissue that originated in the solid mesenchymal tissues.
What is a tumor arising from the endoderm called?
carcinoma. All epithelial-derived tumors are carcinomas, regardless or germ cell layer origin.
What are carcinomas taht frow in glandular patterns called?
adenocarcinomas
What is a pleomorphic adenoma?
when there is divergent diffentiation in tumors, causing mixed cells of origin in a tumor.
What is a teratoma?
a special type of mixed tumor that contains recognizable mature or immature cells representative of more than one germ cell layer ,sometimes all three. They originate from totipotential germ cells, like those present in ovaries and testes.
What is a hamartoma?
a mass of disorganized tissue indigenous to the particular site. May show a mass of mature but disorganized hepaticcells, blood vessels, and possibly bile ducts within the liver or a nodule in the lung containing islands of cartilage, bronchi, and blood vessels. Considered a developmental malformation, but some studies suggest neoplastic origin
What are choristomas?
congenital anomaly consisting of heterotopic rest of cells. (ex: small nodule of well-develped and normally organized pancreatic tissue found in submucosa of stomach, duodenum or small intestine.)
What are the four features that indicate whether benign or malignant?
- differentiation and anaplasia
- rate of growth
- local invasion
- metastasis
Can differentiation and anaplasia be seen in the parenchyme? The stroma?
differentiation and anaplasia can only be seen in the parenchymal cells.
What is desmoplasia?
when cancers induce a dense abundant fibrous stroma, making them hard, so-called scirrhous tumors.
What are malignant neoplasms that are composed of undifferentiated cells called?
anaplastic tumors
What is dysplasia?
loss in the uniformity of individual cells and in their architectural orientation. Dyplastic cells exhibit considerable pleomorphism and often possesss hypercrhomatic nuclei that are abnormally large.
If a tumor lacks a capsule, is it malignant?
not necessarily.
How do malignant neoplasms disseminate?
- seeding within body cavities
- lymphatic spread (carcinomas)
- hematogenous spread (sarcomas)
What is a sentinal lymph node?
first regional lymph node that recieves lymph flow from a primary tumor.
How is xeroderma pigmentosum inherited/
it is an autosomal recessive syndrome of defective DNA repair
What are the 4 primary types of genes that can result in cancer if mutated?
- growth-promotoing proto-oncogenes,
- growth-inhibiting tumor suppressor genes
- genes that regulate apoptosis
- genes involved in DNA repair
What are the two general groups of tumor suppressor genes?
governors - classic tumor suppressor genes such as RB, where mutation of the gne leads to transformation by removing an important brake on cellular proliferation
Guardians - responsible for sensing genomic damage. Choreograph complex damage control response.
What is the most common method of mutation in Burkitt lymphoma?
balanced translocation.
What is aneuploidy?
any chromosome number in humans that is not a multiple of 23
What are microRNAs and how are they involved in cancer?
noncoding, single-stranded RNAs that function as negative regulators of genes. They can be involved in neoplasm if they upregulate production of certain proteins or fail to downregulate.
How do genetic deletions normally cause cancer?
lack of function of tumor suppressor genes
How do balanced translocations normally cause cancer?
overexpression of oncogenes or generation of novel fusion proteins with altered signaling capacity
What will overexpression of miRNAs do in terms of carcinogenesis?
it can reduce the expression of tumor suppressors.
What can deletion or loss of miRNAs do to cause cancer?
lead to overexpression of proto-oncogenes
What is the RAS genes?
most commonly mutated proto-oncogene in human tumors. Member of a family of small G proteins that bind GTP and GDP. Normally they flip back and forth between excited signal-transmitting state and quiescent state. Active when bound to GTP, inactive when bound to GDP.
What mechanism do RAS and ABL commonly play a role in?
they are proteins often involved in downstream signal-transducing. They receive signals from activated growth factor receptors and transmit them to the nucleus through a cascade
What is RAS protein?
the most commonly mutated proto-oncogene. (30% of all tumors). member of small G proteins that bind guanosines. Normally it flips back and forth between active and inactive when it binds to GTP or GDP. When mutated, it cannot hydrolyze bound GTP to GDP and is constantly active.
What is ABL?
proto-oncogene that normally has tyrosine kinase activity. part of the ABL gene is translocated from its normal spot on chromosome 9 to chromosome 22, where it fuses with the BCR gene. The BCR-ABL hybrid protein has unregulated tyrosine kinase activity.
What is the MYC protein?
can either activate or repress transcription of other genes. Is also a key regulator of intermediate metabolism, upregulating genes that promote aerobic glycolysis and increased utilization of glutamine. Mutations in MYC are very common in tumors
What do CDK and the cyclins do?
they control progression of the cell cycle from G1->S->G2->M.
What is the G1 phase?
presynthetic phase
What is the S phase?
DNA synthesis phase
What is the G2 phase?
premitotic phase
What is the M phase?
Mitotic phase.
What stage are quiescent cells in?
G0
Where are the majority of controls in the cell cycle?
between G0->G1 phase
AND
between G1->S phases
What regulates the G1-S transition?
cyclins and CDKs.
What regulates CDK-cyclin complexes?/
CDK inhibitors (CDKIs). They ensure that damaged DNA does not replicate.
What does the G1-S checkpoint monitor?
the integrity of DNA before DNA replication occurs
What does the G2-M checkpoint monitor?
DNA integrity after DNA replication has occured.