CABCO Flashcards
Are alterations in cell cycle regulation that increase cell proliferation sufficient for carcinogenesis and tumorigenesis?
No, other mutations are needed for premalignant cells to acquire traits and behaviors that lead to invasiveness and metastasis
What are the two most desirable therapeutic outcomes when treating cancerous cells?
Apoptosis or permanent cell cycle arrest
It takes how many hours for most human cells to complete the cell cycle?
24 hours
What is the shortest phase in the cell cycle? The longest?
Shortest: mitosis (~1 hour)
Longest: S phase (1/3 to 2/3 cell cycle)
What is the difference between an inactive CDK and an active CDK?
Inactive has no cyclin + a T-loop blocking the active site containing ATP
Active has cyclin bound + phosphorylated T-loop does not block the active site
In what phase of the cell cycle are CDKs not active?
G0
What cyclin-CDK complexes are present in mid G1?
Cyclin D-Cdk 4
Cyclin D-Cdk 6
What cyclin-CDK complexes are present in late G1?
Cyclin E-Cdk 2
What cyclin-CDK complexes are present in S phase?
Cyclin A-Cdk 2
What cyclin-CDK complexes are present in M phase/mitosis?
Cyclin A-Cdk 1
Cyclin B-Cdk 1
What kinase phosphorylates mitotic CDK-cyclin complexes with an inhibitory phosphate?
Wee1
What kinase phosphorylates mitotic CDK-cyclin complexes with an activating phosphate?
CDK Activating Kinase (CAK)
What phosphatase removes inhibitory phosphate from the mitotic CDK-cyclin complex?
Cdc25
What does an activated mitotic CDK-cyclin complex phosphorylate?
Histones, mitotic spindle proteins, lamins
What causes degradation of mitotic cyclins and cohesion proteins holding metaphase chromosomes together?
Anaphase Promotion Complex (APC)
What transcription factor does Rb protein regulate?
E2F
What checkpoint is Rb present in?
G1/S phase
Describe Rb/E2F interaction
Active Rb is bound to E2F, inactivating it
An active G1-Cdk can phosphorylate Rb, inactivating it and releasing E2F. E2F is now free to increase S-phase gene transcription and produce the needed Cyclins (A and E) at this stage
What is the function of the Cip/Kip family of proteins? Name them.
Bind and inactivate dimeric complexes of cyclin D-Cdk4/6, cyclin A-Cdk2 or Cyclin E-Cdk2
p21, p27, and p 57
What is the function of the INK4 family? Name them.
Bind and inactivate Cdk4 and Cdk6 kinases
p15, p16, p18, and p19
What two CDK inhibitors regulate the G1/S transition?
p16 and p27
Ras increases the transcription of what proto-oncogene?
Myc
What does Myc increase the expression of?
Entry into S phase via increased Cyclin D, decreased p27, and increased E2F synthesis & activity
What does p53 do (in general terms)?
Arrest the cell cycle and cause apoptosis
Where are most oncogenic point mutations in p53?
The DNA binding domain
Is p53 active when phosphorylated or dephosphorylated?
Phosphorylated
Inhibits Mdm2 from binding and tagging p53 for degradation
What does it mean to describe p53 mutations as “dominant negative”?
The mutant allele overrides the normal allele
p53 is normally a tetramer and it cannot bind to DNA properly if half of the tetramer is damaged/unable to bind
How does p53 activate the intrinsic pathway of apoptosis?
Via BCL2 family of proteins & cytochrome C release from the mitochondria
What types of cells do tumors contain?
Cancerous AND normal cells (they need the nutrients that normal cells provide)
What type of cancer cell is relatively rare and has a high replicative potential that can effectively “seed” new tumors?
Cancer stem cell
How many viruses are associated with human cancers?
7
What percentage of human cancers are due to viruses?
20%
What is the most common STD in the US?
HPV
How many HPV strains are classified as high-risk?
12
What are the two HPV strains that cause the majority of cervical cancers?
HPV16 and HPV18
What type of tissues does HPV normally infect?
Skin or mucosa (genital tract, oral, nasal)
What two low-risk strains of HPV cause 90% of all genital warts
HPV6 and HPV11
How many genes does a papilloma virus typically have?
8-10
What does HPV transmission require?
A microabrasion
What does HPV’s E7 protein do?
Activates cell cycle progression by binding to Rb
Rb is normally bound to E2F to inhibit cell-cycle progression. E7 binds Rb very tightly, allowing uncontrolled actions of E2F
What does HPV’s E6 protein do?
E6 blocks apoptosis by inducing p53 degradation
E6 complexes with cellular E6AP and this complex can bind to p53 and cause its degradation in the proteosome
The combination of HPV’s E6 and E7 proteins are oncogenic because…?
Their actions result in uncontrolled proliferation AND loss of the ability of the cell to kill itself
Do most people with HPV get cancer?
No, most people clear the virus over time. A small percentage get cancer.
What is the key step in the transition from benign cervical lesion to invasive cervical cancer?
Circular HPV DNA becomes linear and inserts into the host’s genome
What protein is lost in the transition from circular HPV DNA to linear? This protein normally keeps E6 and E7 in check
E2
What are koilocytes?
Cells in the cervical epithelium full of 1000s of HPV viruses
How do you treat persistent HPV infections not associated with abnormal cell changes?
You don’t
What are the three FDA-approved HPV vaccines?
Ceravix, Gardasil, Gardasil 9
What cells of the epithelium does HPV first infect?
Basal cells
What component of the HPV capsid do most of the vaccines target?
L1 protein
What enzyme has increased activity in Chronic Lymphocytic Leukemia?
Bruton’s tyrosine kinase
Can capacitated patients refuse life-sustaining treatment?
Yes
Can patients use advanced directives to refuse life sustaining treatment when they become incapacitated?
Yes
What is the ethical and legal difference between withholding and withdrawal of life sustaining treatment?
There isn’t one
When are advanced directives legally enforceable?
When a patient loses decisional capacity
Can ordinary power of attorney be used for decision-making for incapacitated patients?
No, only a durable power of attorney continues through incapacity
Define neoplasia
general process of new growth
Define neoplasm
A new growth
Define cancer
general term for all malignant tumors
Are tumor and malignancy synonymous?
No
Tumor = neoplasm
Name of benign and malignant tumors affecting squamous epithelium?
Benign: squamous papilloma
Malignant: squamous cell carcinoma
Name of benign and malignant tumors affecting glandular epithelium
Benign: adenoma
Malignant: adenocarcinoma
Name of benign and malignant tumors affecting surface epithelium?
Benign: papilloma
Malignant: papillary carcinoma
Name of benign and malignant tumors affecting smooth muscle
Benign: leiomyoma
Malignant: leiomyosarcoma
Name of benign and malignant tumors affecting striated muscle?
Benign: Rhabdomyoma
Malignant: Rhabdomyosarcoma
Name of benign and malignant tumors affecting blood vessels?
Benign: Hemangioma
Malignant: Angiosarcoma
Name of benign and malignant tumors affecting fat?
Benign: Lipoma
Malignant: Liposarcoma
Name of benign and malignant tumors affecting cartilage?
Benign: chondroma
Malignant: chondrosarcoma
Name of benign and malignant tumors affecting bone?
Benign: osteoma
Malignant: osteosarcome
Name of benign and malignant tumors affecting fibroblasts?
Benign: fibroma
Malignant: fibrosarcoma
Name of benign and malignant tumors affecting melanocytes?
Benign: nevus
Malignant: malignant melanoma
Name of benign and malignant tumors affecting totipotent germ cells?
Benign: mature teratoma
Malignant: immature teratoma (teratocarcinoma)
Name of benign and malignant tumors affecting lymph nodes/bone marrow?
Benign: low grade lymphoma
Malignant: high grade lymphoma
Six steps in the invasion-metastasis cascade?
- Local invasion
- Intravasation into blood/lymphatic vessels
- Transit in vessel
- Arrest/extravasation into distant tissue
- Micrometastasis formation (small nodules)
- Colonization
What is the first transformation cancer cells must make in order to complete metastasis?
Epithelial to mesenchymal transition
Is metastasis an efficient or inefficient process?
Very inefficient
Less than 0.01% of cancer cells in circulation develop into metastases
Define hypertrophy
Increase in tissue mass without cellular proliferation (aka increase in cell size)
Define hyperplasia
Increase in tissue mass due to an increase in cell number
Define metaplasia
A reversible change in which a differentiated cell type is replaced by another cell type. Most common in mucosal/epithelial surfaces
Usually happens in response to a stimulus
Becomes a problem when stimulus/irritant continues and produces genetic changes leading to autologous growth and cancer
What are four types of non-neoplastic growth & differentiation?
- Reparative proliferation (granulation tissue)
- Hypertrophy
- Hyperplasia
- Metaplasia
Characteristics of benign neoplasms?
Autonomous growth that is slow and progressive
Growth by expansion NOT invasion
Encapsulation/clear demarcation from normal tissue
Cells with high degree of differentiation/preserved architecture
Define ectopic
Normal tissue in abnormal location
Define hamartoma
normal tissue components in an abnormal/disorganized configuration (“at home”)
Define choristomas/heterotopia
Normal tissue but in the wrong place
Ex: normal pancreatic tissue ectopically present in the wall of the stomach
Define polyp
Grossly visible growth projecting from a surface, often a mucosal surface
General term. Can be hyperplastic (non-neoplastic), benign, or malignant
Define hyperplastic polyp
Most common type of colonic polyp; lacks malignant potential . Has “saw-tooth”/serrated/tufted appearance
In many organs/locations
Is benign neoplastic growth reversible?
“the process is not generally considerable reversible”
What does “oma” mean?
Tumor (no distinction between benign or malignant though!)
What is Von Hippel-Lindau Syndrome?
Autosomal dominant genetic condition characterized by visceral cysts, benign masses, and the potential for malignant transformation in multiple organ systems
Clinical features of Von Hippel-Lindau Syndrome?
Eye tumor, brain tumor, kidney tumor, adrenal gland tumor, pancreatic tumor, Cafe Au Lait spots, CVS (strokes and heart attacks)
Most common type of disease-causing mutation?
Single point mutation
Three ways proto-oncogenes are converted into oncogenes?
- Point mutation
- Gene amplification
- Chromosomal rearrangement
What does Ras bind in its active state? Does this induce or inhibit cell growth?
GTP
Induces cell growth
What oncogene in responsible for Neuroblastoma? What is its mechanism from proto-oncogene to oncogene?
N-myc
Amplification
How do Burkitt lymphoma tumor cells appear on H&E?
Round, homogenous, and display a high mitotic rate
Chromosomal translocation responsible for Burkitt lymphoma?
8 and 14 (14q has new IgH-myc gene)
Places the myc gene adjacent to IgH enhancer/promoter
Chromosomal translocation responsible for Chronic Myelogenous leukemia (CML)?
9 and 22 (9q has new Bcr-Abl gene)
Bcr-Abl is a constitutively active tyrosine kinase that leads to cell growth
What drug inhibits Bcr-Abl function?
Imatinib (Gleevec)
Binds into the ATP site of Bcr-Abl and inhibits tyrosine kinase functionality
Gleevec is a synthetic ATP mimic
Effect of mutations on tumor suppressor genes?
Inactivation
Effect of mutations on oncogenes?
Activation
First tumor suppressor gene identified?
Rb
13q
Main job of Rb?
“Molecular policeman” of the cell cycle: serves as a guard at the G1/S transition
What is the most commonly mutated gene in human cancer?
p53
95% of p53 mutations are found where?
point mutations in the DNA-binding domain
The cancer cell phenotype is (dominant or recessive) to the normal cell phenotype?
Recessive
per cell fusion experiment
Are viral oncogenes derived from viral or host genomes?
Host
Define log cell kill
A given dose kills a fixed percentage of cells
Note: established in vitro, not in vivo
Define dose dependent
Different depending on whether or not the agent is cell cycle specific
The growth fraction of tumor cells depends on what?
The size of the tumor
As tumor size increases, growth fraction decreases
When is chemotherapy most effective?
When cell turnover is highest
When is cell turnover highest?
When tumor volume is below the level of detection (10^9 tumor cells)
Log cell kill effect depends on the tumor ______ at diagnosis
volume
What results in the best chance of cure?
Dose intensity - the concept that the highest dose at the most frequent intervals will result in the best chance of cure
If a tumor has a stable growth fraction, a given dose of drug will kill what?
A fixed percentage of tumor cells regardless of the tumor mass
** he stressed this in class **
Define palliative chemotherapy
Chemotherapy given to patients with metastatic/incurable cancer with the intent of prolonging life or alleviating symptoms
Define curative chemotherapy
Chemotherapy, almost always combination of drugs, given with the intent of inducing remission and curing the patient
Used with testicular cancer, lymphomas, leukemia, and a few solid tumors
Define adjuvant chemotherapy
Chemotherapy given after a local procedure (surgery or radiotherapy) with the intent of eradicating microscopic metastases
Commonly used in breast cancer, colon cancer, and selected other tumors
*** Patients generally do not have clinically detectable metastases
Define neoadjuvant chemotherapy
Chemotherapy given when a tumor is large/unresectable with the intent of making it more amenable to local therapy and at the same time treating the subclinical metastatic diseases
What is the order of gene mutations seen in colon cancer progression?
- APC/B-catenin
- K-RAS
- p53
Two categories of molecular changes seen in colon cancer development?
- Genomic changes/genetic (chromosomal instability or microsatellite instability)
- DNA methylation/epigenetic
In which part of the colon are hyperplastic polyps most common?
Left colon
Result from decreased cell turnover; no malignant potential
What are three types of adneomas/neoplastic polyps found in the colon?
- Tubular adneoma
- Villous adneoma
- Sessile serrated adenoma
Define tubular adenoma
small, pedunculated, “tubular glands,” and often have a stalk
Nucleus appears elongated
Define villous adenoma
larger, long, slender villi
Has a wide base and grows as a sessile (“attached along the base of lesion”) rather than as a pedunculated lesion with a long stalk
Define sessile serrated adenoma
Similar to hyperplastic polyps but crypt dilation and budding into the lamina propria (wider base)
In which portion of the colon are sessile serrated adneomas most commonly found?
Right colon
What precedes the development of macroscopic polyp (adenoma)?
An aberrant crypt focus (ACF)
What are the precursor lesions in Familial Adenomatous Polyposis (FAP)?
aberrant crypt foci (ACF)
Outside of the colon, where do lesions typically present in those with FAP?
Retinal lesions, gastric & duodenal polyps, desmoid tumors
What is Gardner syndrome?
FAP, osteomas, skin cysts
What is Turcot syndrome?
FAP, brain tumors
What germline mutation is present in people with FAP?
APC gene
** know this!!!
What does APC regulate?
B-catenin
When Wnt signaling is present, APC is constantly degraded and B-catenin signaling is always “on”
This leads to constitutive proliferation
What precursor lesions are present in patients with Lynch Syndrome (HNPCC)?
Tubular adenomas (but smaller and flatter)
Median age of CRC diagnosis in HNPCC? FAP?
HNPCC: 60
FAP: 35-40
Where is CRC most commonly present in those with Lynch Syndrome?
right colon
People with Lynch Syndrome are at a higher risk for what other cancers?
Endometrial, small bowel, ovarian, gastric and ureteral
What is the distinctive histology present in Lynch Syndrome?
Mucinous and “medullary/solid” differentiation
Germline mutations in Lynch Syndrome?
hMLH1, hMSH2, hPMS1, hPMS2, hMSH6
What gene is methylated/silenced in SSA adenomas?
MLH1
Which side of the colon has more goblet cells?
Left side
Which side of the colon has more Paneth cells?
Right side
Most common neoplastic polyp?
Tubular adenoma
Favorite places for colon cancer metastasis?
Lymph nodes, liver, lungs, and bones
What cancer(s) are associated with Epstein-Barr virus?
Nasopharyngeal carcinoma
Burkitt lymphoma
What cancer(s) are associated with human herpes virus type 8 (HHV8)?
Kaposi sarcoma
What cancer(s) are associated with Human T-cell leukemia/lymphoma virus (HTLV-1)?
T-cell leukemia/lymphoma
What cancer(s) are associated with Human T-cell leukemia/lymphoma virus (HTLV-2)?
Hairy cell leukemia (very weak association)
What cancer(s) are associated with HPV 16 & 18?
Cervical, head & neck cancers
What cancer(s) are associated with Hepatitis B & C?
Hepatocellular carcinoma
What are examples of AIDS-defining cancers?
Kaposi sarcoma, non-hodgkin lymphoma, invasive cervical cancer
What are examples of cancers that can develop in persons with HIV infection while they are being treated with HAART?
Hepatocellular carcinoma, anal cancer, hodgkin lymphoma
Note: NON-hodgkin lymphoma is an AIDS-defining cancer. Don’t let Winter trick you!!!
What is Post-transplant lymphoproliferative disorder (PTLD)?
A neoplasm that can develop after organ transplantation due to immunosuppression (linked to EBV B-cell infection)
List the three tumor markers Winter gave in his presentation
M-spike, PSA, CEA
What type of lymphocyte do we need for tumor resistance?
T cells
What is “cancer immunoediting”?
Cancer cells that escape immune system recognition are able to survive and proliferate
“selective outgrowth of antigen-negative variants”
What are three ways tumors escape immune recognition?
“Greased pig phenomenon”
- Loss of MHC 1 due to TAP or proteasome mutation
- Loss of adhesion molecule expression
- Lack of B7 expression (no co-stimulus -> leads to T Cell anergy
How do tumor cells prevent killing by NK cells?
They express other MHC 1 molecules that prevent this
just missing the MHC 1 class that T cells interact with
What two cytokines do tumors secrete that suppresses the immune system?
- TGF-beta
- IDO enzyme
Both of these suppress CD4 and CD8 cells
What does TGF-beta activate?
Tregs (CD4+, CD25+, FoxP3+)
What do Tregs secrete?
TGF-beta, IL-10 (also suppresses immune response!), and IDO
How can a tumor cell induce apoptosis in a CD8 T cell?
Tumor Fas-ligand binds to CD8 Fas and causes apoptosis of CD8 cell
What two tissues lack lymphatics?
Brain and gonads
How do tumor cells mask themselves?
With connective tissue and glycocalyx molecules
What does Anti-CD22-pseudomonas toxin do?
It is a toxin-labeled antibody that binds to CD22 on tumor cells. The tumor cell internalizes the receptor-Ab conjugate and dies
Causes remission in 2/3 of hairy cell leukemia patients
How can antibodies be used to attack tumor cells?
Monoclonal antibodies that make it easier for NK cells to find the tumor cells
Toxin, radiation or drug-labeled antibodies
Does immunizing cancer patients with tumor proteins mixed with bacterial adjuvants work?
Nope, largely ineffective
What are Immune Stimulatory Complexes (ISCOMs)?
lipid micelles containing tumor antigen
APCs take up these ISCOMs and present the antigens to CD8 t cells. Now they’re activated and looking for tumor cells
What are Lymphokine-activated killers (LAKs)?
mononuclear cells are isolated from peripheral blood and given IL-2 (T cell growth factor!). Enhanced CD8 t cells & NK cells are infused back into the patient
What are Tumor-Infiltrating lymphocytes (TILs)?
Lymphocytes and NK cells are isolated from a tumor and given IL-2 (T cell growth factor!). Enhanced CD8 t cells & NK cells are infused back into the patient
What is KRAS?
Proto-oncogene GTPase
Oncogenic form is stuck in the “on” position with GTP
What are “CAR-T cells”?
Chimeric antigen receptor modified T cells
A patient’s t cells are modified to include a receptor that targets tumor cell antigen
Structure is a single chain fragment that is mostly variable region
What kind of malignancies have CAR-T cells been effective in treating?
Hematologic
How can CAR-T cells be made effective against solid tumors?
Diapedesis into the solid tumor needs to be increased
This can be done by re-engineering CD6 (5HS) to increase transit into the tumor
What are immune checkpoint inhibitors?
Normally, T-cell signaling can lead to down-regulation of T-cell actions; this can be via CTLA4-B7 or PD1-PDL1 interactions
Monoclonal antibodies, aka checkpoint inhibitors, can be developed that bind to PDL1, PD1, and CTLA4 and stop this down regulation
What immunologic toxicities are caused by anti-PD1/anti-PDL1 monoclonal antibodies?
Immune-related adverse reactions (irARs) like pneumonitis, diarrhea/colitis, vitiligo, T1DM, thyroid changes, etc
What does CD47 do?
It’s a protein present on tumor cells that binds to SIPalpha on macrophages and says “don’t eat me!”
An anti-CD47 monoclonal antibody can bind to CD47 and increase macrophage phagocytosis
What type of biopsy just gives cells?
Fine needle
What type of biopsy gives architecture and allows more tests to be performed?
Core needle biopsy
What type of biopsy is the gold standard for initially assessing image detectable lesions in the breast?
Core needle
What percentage of biopsies should require open surgical biopsy?
5-10%
What is en bloc resection?
Removing the cancer with a rim of normal tissue
Well-established benefit in clinical trials for most cancers
What is the “gold standard” trial for breast cancer surgery? What did it show?
NSABP B-06
Mastectomy = lumpectomy + radiation
Lumpectomy with radiation is better than without
In which types of cancer surgeries is laparoscopic technique not an accepted surgical treatment?
Ovarian, adrenal, thyroid, uterine
OAT U
Screening is best understood as _______ _______?
Therapeutic intervention
Possible good outcomes of screening?
Decreased morbidity and mortality
Possible bad outcomes of screening?
Side effects, labeling with a diagnosis, false positives & negatives, over-diagnosis
Sources of bias in screening?
Selection bias, lead-time bias, and length-time bias
What is “up staging”?
Introduction of a new staging modality such as CT, PET, or surgical staging that gives one more accurate staging
What is the Will Rogers effect?
New staging makes it look like the survival is better for each stage but really patients have just migrated from one stage to another
All stages of the disease look better, but the overall population has the same survival
What is the number needed to screen?
The number of individuals you would need to screen to achieve one additional desirable outcome
1/Absolute risk reduction
he said this was an exam question!!!
How do you calculate absolute risk reduction?
Control Event Risk - Experimental Event Risk = ARR
What is fallacy of division?
What is true for the group is true for each individual
What is fallacy of composition?
What is true for an individual is also true of the group
Majority of cancer survivors are over what age?
65
What percentage of children with cancer will be cured?
80%
What are late effects of cancer treatment?
Complications that occur or persist more than 5 years from the end of therapy
They are unrecognized toxicities that are absent or subclinical at the end of therapy but manifest later
Ex: growth & development abnormalities, infertility, psychosocial effects, problems with vital organ function, etc
What are long-term effects of cancer treatment?
Side effects or complications of treatment that begin during treatment and continue beyond the end of treatment
ex: lymphedema, malabsorption, loss of voice
Which cancer treatment method has systemic effects?
Chemotherapy
What are the culprits of cardiac toxicity following cancer treatment?
Radiation
Anthracycline-type chemotherapy (Doxorubicin)
Tyrosine kinase inhibitors (Pazopanib, Sunitinib, Nilotinib)
Monoclonal antibodies (Trastuzumab, Bevacizumab)
How long after anthracycline-therapy is cardiac risk elevated?
5 years
The risk of second cancer is highest for who?
Those diagnosed at a younger age
because their bodies are growing/DNA is active when initial treatment is occurring
When is the risk for a second cancer highest?
Within first 5 years after initial cancer but risk persists beyond 10 years from diagnosis
What can be viewed as a cell cycle disease?
Cancer
What three phases/blocks of treatment are used to treat childhood leukemia?
Induction, consolidation, maintenance
What were the downsides of craniospinal radiation used in the 1970s to treat leukemia?
Myelosuppression, growth issues, altered intellectual and psychomotor function, endocrine abnormalities
What treatment combination was found to be equivalent to brain radiation?
Intensive systemic chemotherapy and intrathecal therapy combined
(intrathecal therapy was less effective than radiation when less intensive chemo was used)
What is the Goldie Coldman hypothesis?
Intensive cytoreduction leads to fewer surviving tumor cells to undergo mutation & lead to resistance
“If mutations are chance events during cell division, having more cells around increases the risk of mutation leading to resistance.”
Combination of what three induction phase drugs brought remission rates to greater than 95%?
Vincristine + steroid + asparaginase
Note: anthracycline could be added to further improve remission rates but its highly toxic
What is the criteria for standard risk pediatric leukemia patients? High risk?
Standard: between 1 and 10 years old; WBC less than 50,000/mL
High: Over 10 and WBC greater than 50,000/mL
How many leukemia cells are left after induction phase treatment? Why?
~ 10 billion
They persist due to resistance, sanctuary sites, quiescent state (were not dividing when chemo was given)
What are two improvements of post-induction therapy?
- Intensifying therapy of slow responders (if minimal residual disease is left then increase therapy)
- Identifying low/high risk subgroups through cytogenetics (i.e. Philadelphia chromosome, MLL rearrangements, hypoploidy, etc)
What is the Norton Simon hypothesis?
Cells remaining post-induction are relatively/absolutely resistant; late/delayed intensification (new agents) may be beneficial here
He gave the example of a second round of induction and consolidation treatments (dexamethasone + anthracycline (low risk) or doxorubicin (high-risk)
Has the introduction of new chemotherapy agents played a large or small role in pediatric leukemia outcome improvements?
Small role
Major improvements came via clinical trials assessing traditional drugs
Disease-free survival rate for Ph+ Acute Lymphoblastic Leukemia with chemotherapy alone and with BMT from sibling?
Chemo: 20%
BMT from sibling: 60%
What gene is expressed in Ph-like acute lymphoblastic leukemia?
R8
Note: their outcomes are inferior to those who are actually Ph+
What is the single best criterion of malignancy?
Metastasis
What is the most common benign neoplasm of the female breast?
Fibroadenoma
What is the most common benign tumor of the salivary glands?
Pleomorphic adenoma
What features reflect a lack of cell differentiation/become more prominent in malignant tumors?
- Variation in cell size (pleomorphism)
- Increased nuclear size (higher N:C ratio)
- Increased DNA content & irregular nuclear borders
- Large nucleoli
- Increased mitoses
- Abnormal mitoses
In what type of cancer do we see Reed-Sternberg cells (“owl eyes”) on H&E?
Hodgkin Lymphoma
In what type of tumor do we see multipolar mitotic figures?
Wilms tumor
In what type of cancer will we see keratin?
Squamous cell carcinoma
If a cancer cell is TTF+ and CK7+, what type of cancer is it?
Adenocarcinoma
If a cancer cell is p63+, what type of cell is it?
Squamous cell carcinoma
What two organs are most commonly involved with metastatic cancer?
Lungs and liver
What property (or finding) gives a tumor the potential opportunity for metastasis?
Invasion through the basement membrane (gaining access to blood vessels or lymphatics)
What is the most common general type of human cancer?
Carcinoma
What are the two main types of carcinoma?
Squamous cell carcinoma and adenocarcinoma
How common are sarcomas?
Less than 1% of all human malignant tumors
When are tumor cells most chemo-sensitive?
When they are small and have a high growth fraction
What is growth fraction?
The fraction of tumor cells that are actively dividing
What does the Norton-Simon hypothesis predict?
Greater log-kill in smaller tumors due to rapid growth and supports chemotherapy in the postoperative setting
Five forms of cancer immunotherapy?
- Bone marrow transplant
- Monoclonal antibodies
- Cancer vaccines
- Checkpoint inhibitors
- CAR T cells
What is a dendritic cell vaccine?
Its used to enhance a patient’s T cell immunity
Dendritic cells are pulsed with tumor antigens and then injected into the patient. DCs present tumor antigen to the patient’s T cells and then tumor-specific T-cells are activated
Most common malignancy in children?
B-cell acute lymphoblastic leukemia (ALL)
What are three targets of targeted therapy?
- Oncogenic signaling pathways (EGF, MAP kinase, BCR-ABL)
- Angiogenesis (VEGF)
- Apoptotic machinery (HDAC, proteasome inhibitors)
What is a basket trial for precision medicine?
Genomic aberrations are recurrent across multiple organ sites & the presence of a specific mutation may be more predicative of drug response
aka people with similar mutations, not necessarily in the same organ, are enrolled to see if a treatment approved in another disease will work for their disease or a rare one
What is an umbrella trial?
Evaluates many treatments (aka many “treatment arms”) within the same cancer type
What is a super-umbrella trial?
Captures umbrella trial AND basket trial under on super umbrella. Lots of arms that people go be assigned
Downside is that patients could be eligible for multiple arms or that the trial may require a large number of drugs and biomarkers
What are SERMS? Example of one?
Selective Estrogen Receptor Modulators
Ex: Tamoxifen
What is the cause of non-small cell lung cancer?
EGFR is aberrantly activated (oncogene)
Activation due to overexpression of receptor or mutations that cause constitutive activation of receptor tyrosine kinase activity
“oncogene addiction”
What receptor is overexpressed in 25-30% of patients with metastatic breast cancer?
HER-2/neu (human epidermal growth factor receptor 2)
95% of Chronic Myelogenous Leukemia (CML) are associated with what?
The Philadelphia chromosome t(9;22)
Joins BCR locus on chromosome 22 with the ABL locus on chromosome 9 to make the mutant tyrosine kinase BCR-ABL
What type of mutation is found in 60% of melanomas?
BRAF mutations
BRAF is a component of the MAP kinase pathway that transmit growth-stimulatory signals from the cell surface to the nucleus
90% of BRAF mutations affect a single amino acid residue. What is it?
V600E
What is the equation for how x-rays interact with matter?
High energy x-ray + water —-> H20^+ + e^-
H20^+ quickly decays into H+ and OH* (free radical)
Free radical causes DNA damage
DNA damage leads to cell death
When do we see the biologic effects of DNA damage after radiation?
Days to weeks after the lethal event
Most cells do not show evidence of radiation damage until they attempt to divide
DNA damage can be lethal and ______?
Sublethal
Sublethal damage can be repaired
Do cancer cells take longer or shorter to repair than normal cells?
Longer
Fractionating radiation dosage takes advantage of this! The same small dose is applied over multiple exposures so less damage is caused to normal cells & they can repair themselves
What are the two different types of radiation used?
- Teletherapy (external beam RT) - photon therapy/x-rays, most common
- Bracytherapy (internal RT) - radiation implants, ingested radioactive pills, intravascular radiation injections
What is 3D conformal RT?
3D conformal radiation therapyis a cancertreatmentthat shapes theradiation beams to match the shape of the tumor
What is intensity modulated radiotherapy (IMRT)?
Divided into various beamlets; varying intensities allow you to conform to the shape and carve out things you don’t want to hit like the spinal cord
What is Stereotactic Body Radiation (SBRT) or Stereotactic Ablative Radiotherapy (SABR)?
Administration of very high doses of radiation, using several beams of various intensities aimed at different angles to precisely target the tumor
SBRT is typically used to treat small, well-defined tumors
What are the goals of CT simulation?
Immobilization and reproducibility
In which age group is cancer the #1 cause of death?
45-64
Are most cancer cytotoxic agents specific or nonspecific?
Nonspecific
Hereditary cancer gene in Familial Melanoma?
p16INK
Hereditary cancer gene in Li Fraumeni Syndrome?
p53
Hereditary cancer gene in Familial Gastric Cancer?
CDH1
The occurrence of translocations as a sole karyotypic event in carcinomas are common/uncommon?
Uncommon
Generally associated with loss of heterozygosity, specific gene mutations, or aberrant patterns of expression
Tumors of ______ origin are often associated with translocations thought to be causally related to the development of the neoplasia
mesodermal
What was the first therapeutic target?
Estrogen
What type of non-small cell lung cancer has the worst survival: squamous or adenocarcinoma?
Squamous
Most of the research and treatment effort has been focused on adenocarcinoma