Neoplasia 2 Flashcards
_________ is the development of secondary deposits of a tumor in a distant site.
Metastasis
True or False: Metastasis is considered the hallmark of malignancy although it is not always seen.
True
True or False: All types of cancer metastasize at a similarly fast speed.
False, some more rapid than others
____% of newly diagnosed patients with solid tumors will already have obvious metastasis.
30
What is “occult metastasis?”
hidden; so small that they’re difficult to detect
In general, the _______ and more ________ a tumor is, the more likely it is to metastasize.
larger more anaplastic (less differentiated)
What are the three pathways for metastasis?
- seeding within body cavities
- lymphatic spread
- hematogenous spread
Mesothelioma is a cancer that metastasizes through which pathway?
seeding within the body cavity (lungs)
Which type of metastasis is common for carcinomas?
lymphatic spread (the lymph nodes are involved)
Which type of metastasis is common for sarcomas?
hematogenous spread (most often affects the liver and lungs)
In regards to metastasis, why is melanoma so dangerous?
it is not restricted to one pathway. Spread occurs through lymph, blood, or both
________ is a field of study that will often provide clues as to the etiology of or contributing factors to cancer development.
epidemiology
Cigarettes and alcohol are ______ in the development of oral cancer.
synergistic
What is the #1 cause of cancerous death in both men and women?
lung
Which type of cancer seemed to rise in women over the last forty years?
lung
True or False: The prevalence of uterine cancer is decreasing.
True (thanks, pap smear and cervical screenings)
What proportion of cancer risk is attributable to ENVIRONMENTAL sources?
2/3rds (65%)
What type of cancer is 7 times more frequent in Japan than in the U.S?
stomach
What types of cancer are 5 times less common in Japan than in the U.S?
breast and prostate
Why is age associated with an increased frequency of cancer (two reasons)?
- accumulation of somatic mutations
2. decreased immune competence
True or False: Between 1962 and 2008 there was a dramatic increase in 5-year survival rate for child cancers.
True
Cancer occurs in every 1 of ____ people.
5
True or False: Cancer is a hereditary disease.
False, it is a predisposing factor for some cancers but well-defined genetic influences only occur in a few types
What are the three broad categories of genetic predisposition to cancer?
- Inherited cancer syndromes
- Familial cancers
- Defective DNA repair
Inherited cancer syndromes are usually due to ______ mutation and generally show _______ ______ transmission.
a single gene
autosomal dominant
True or False: Inherited cancer syndromes are usually due to autosomal recessive transmission.
false,
- usually autosomal DOMINANT
- *however: Xeroderma pigmentosum is autosomal recessive and causes defective repair of DNA
What are the characteristics of “familial cancers?”
- early age at onset
- tumors in two or more close relatives of the index
- multiple or bilateral tumors
_____, ______, ______, and ______ malignancies have been reported to occur in familial patterns.
colon, breast, ovary, brain
Xeroderma Pigmentosum is an autosomal recessive syndrome that results from defective _______.
DNA Repair
-ultraviolet induced dimerization does not repair itself
True or False: 50% of human cancers have an identifiable heritable basis.
False, only 5-10%
What are acquired preneoplastic disorders?
conditions that are associated with a significantly increased cancer risk.
Persistent regenerative cell replication (liver), villous adenomas of the colon (polyps), and ______ of the oral or genital mucosa are examples of acquired preneoplastic disorders.
leukoplakia
True or False: Leukoplakia can be a carcinoma or a callus, but either one is considered fertile soil.
True, the “abnormal mass of tissue” is fertile ground for production of carcinoma
Nonlethal genetic damage, often due to _____, ______, viruses, or inherited mutations, is central to all cancers.
chemicals
radiation
What are the three classes of normal regulatory genes that are often affected in carcinogenesis?
- protooncogenes (growth promoting)
- cancer suppressor genes (growth inhibiting)
- apoptosis genes
________ genes will indirectly contribute to cancer development because acquired mutation are maintained
DNA repair
Carcinogenesis is a multi-step process at both the ____ and _____ levels.
phenotypic
genetic
________ are normal functional components of the cell that are transformed into oncogenes.
protooncogenes
What type of proteins do oncogenes encode for?
oncoproteins (duh!)
How do oncogenes differ from the protooncogene?
they are similar (or identical) to the normal gene but they LACK REGULATION
In what two ways are protooncogenes transformed to oncogenes?
- Structural mutation of a gene = abnormal product
2. Altered regulation of expression = increased production of growth-promoting proteins
All normal cells require ____ ____ stimulation to undergo proliferation.
growth factor
Glioblastoma (brain tumor) results from the over expression of _______.
Platelet derived growth factor
Some sarcomas are associated with the over expression of ______.
TGF alpha
What is the effect of the overexpression of growth factor receptors?
makes cancer cells hyperresponsive to even normal levels of Growth Factor
What are two commonly documented mutations associated with overexpression of GF Receptors?
ERB B1 and B2 (epidermal growth factor receptors)
What is a common Signal Transducing Protein that is associated with 30% of human tumors?
RAS
Mutant RAS remains in its _______ form.
active (stimulating constant cell proliferation)
True or False: Normal (non-mutated) RAS is inactivated quickly.
True
Which Nuclear Transcription Factor gene is most commonly affected?
MYC gene
The over-expression of MYC gene leads to continuous activation of __________ which drives the cell to divide.
Cyclin-Dependent Kinases
_______ is associated with an over-expression of MYC gene.
Burkitt’s Lymphoma
Orderly progression of the cell cycle is orchestrated by _____ binding to _____.
CDK to cyclins
Activity of CDK’s is regulated by ____ families of CDK inhibitors.
two
Dysregulation of CDK activity will favor ______.
cell proliferation
__________ inhibit cell proliferation.
tumor suppressor genes
What was the first discovered tumor supporessor gene?
RB
What is Knudson’s “Two Hit Hypothesis?”
two mutations are required to induce retinoblastoma
- both normal RB alleles must be inactivated
- if inherit one defective copy, the other must undergo mutation for the tumor to develop
What do tumor suppressor genes do?
- regulate cell cycle
- regulate cell adhesion
- regulate signal transduction
What is the most common of all tumor suppressor genes that is associated with cancers/tumors?
TP53 (p53)
True or False: Heterozygous loss of p53 is found in virtually every type of cancer.
False: homozygous loss of TP53 (p53) is found in virtually all forms of cancer
What does the TP53 product normally do for the cell?
acts in the nucleus to inhibit cell cycle progression
Normally, when TP53 accumulates (after DNA damage), the ________ is inhibited to allow time to repair DNA.
cell proliferation
What does TP53 cause in the case of failed repair mechanisms?
apoptosis
True or False: With a homozygous loss of p53, DNA damage goes unrepaired.
True
In Li-Fraumeni Syndrome, one allele defect of TP53 is inherited. What influence does this have?
25 times increased risk for malignancy before age 50!
