Oncology I Flashcards
benign tumors and malignant tumors both form due to initial mutations in normal cell populations. what is the difference in the processes which form benign tumors vs. malignant ones?
after the initial mutation which causes tumor formation, malignant tumors will go on to develop additional mutations, overexpressions and altered enzyme pathways, they will develop the capacity for invasion and metasasis and acquire features of malignancy, benign tumors will maintain well-controlled growth and benign histologic features
put the following stages of tumor development in order: metastatic melanoma, dysplastic nevus, benign nevus, radial growth phase, vertical growth phase
- benign nevus
- dysplastic nevus
- radial growth phase
- vertical growth phase
- metastatic melanoma
what is the most commonly mutated oncogene?
RAS
how are growth factor receptors involved in squamous cell lung cancer and breast cancer?
Growth factor receptors are overexpressed in squamous cell lung cancer (ERBB1) and breast cancer (HER2/NEU)
describe how each of the following features are affected in malignancy:
- ratio of nucleus to cytoplasm
- appearance of the nucleus (3 changes)
- mitotic rate
- increased Nucleus:cytoplasm ratio
- nucleus is pleomorphic, hyperchromatic, with prominent nucleoli
- increased mitotic rate
what are “keratin peals”?
keratin pears are seen in squamous cell carcinoma, whorl of tumor cells with keratin production in the center
squamous cells have tonofilaments. what are tonofilaments?
tonofilaments are intercellular bridges which are perpendicular between tumor cells
what are the cells of origin in sarcomas?
mesenchymal tissue
desmoplasia
fibrosis and connective tissue growth seen in carcinomas
do most breast carcinomas arise from acini (glands) or from duct epithelium?
duct epithelium
why does desmoplasia occur?
tissue attempts to “contain” the tumor with a fibroblastic response at primary sites and metastatic sites
what changes must take place in tumor cells in order for them to invade the basement membrane and ECM? Mutations in what gene are typically involved?
Mutation of E-cadherin allows for loosening of tumor cells to help them prepare to invade the Basement membrane (mutations in SNAIL and TWIST, which regulate E-cadherin are also seen)
Degradation of the BM and ECM requires the tumor cells to begin expressing what types of proteins?
tumor cells will begin secreting collagenases, urokinase plasminogen activator, gelatinase, etc.
how do to surface proteins change to allow tumor cells to interact with ECM proteins?
tumor cells will begin expressing integrins which have affinity for laminin and other ECM proteins
what genes are critical in the tumor’s ability to promote vasculogenesis?
the tumor expresses VEGF and HIF-1A (hypoxia inducible factor), as well as angiogenin and TGF-a,B
why are chemokine receptors important in metastasis?
chemokine receptors on tumor cells bind to certain target tissues, i.e. tumor cells expressing CCR7 will bind at target tissues such as lung which express CCL21
do carcinomas travel through arteries, veins or lymphatics? what about sarcomas? what are the target sites of each?
carcinomas: travel through lymphatics to regional lymph nodes
sarcomas: travel through veins to lungs and bone
metastases to the lung most commonly arise from what sites of origin?
colorectal, breast, kidney, HCC
what cancers typically metastasize to the liver?
colorectal, pancreas, GI, lung breast
what cancers commonly metastasize to the bone?
breast, prostate, renal
what cancers typically metastasize to the brain?
lung, breast, melanoma, renal
Virchow’s node
supraclavicular node, metastasis from gastric adenocarcinoma
Krukenberg tumor
bilateral metastatic malignancy to the ovaries from primary GI malignancy
what are sentinel lymph nodes?
the first node that receives lymphatic drainage when dye is injected into the tumor, helps determine where cancer has/could metastasize
which of the following might you not treat immediately upon diagnosis: ALL or CLL. why? which is more aggressive? which is more curable?
CLL, if asymptomatic, does not require treatment
ALL: more aggressive, always treat, more curable
what is the difference between a lymphoma and a leukemia
leukemia: begins in the bone marrow or blood, lymphocytes and myeloid cells affected
lymphoma: begins in bone marrow, WBC affected are lymphocytes only (Not myeloid cells)
what immune cells are involved in ALL?
B-cells and T-cells
is lymphadenopathy seen more in ALL or CLL?
seen more in CLL because CLL involves mature lymphocytes
is this smear ALL or CLL? how do you know? what are the relevant features?
this is CLL, small, round lymphocytes, clumpy chromatin, NO nucleoli, presence of platelets
is this ALL or CLL? how do you know? what are the relevant features?
this is ALL, BIG lymphocytes, lighter “open chromatin,” nucleoli, no granules
risk factors for ALL
radiation exposure, trisomy 21
typical patient presentation of ALL
cytopenia: bleeding, infection, fatigue, dizziness
fever
bone pain
(lymphadenopathy is RARE)
state whether each of the following more closely aligns with presentation of ALL or CLL: weight loss over 5 years, rash, mediastinal mass, lymphadenopathy, anemia, ecchymoses
anemia, ecchymoses, rash & mediastinal mass: ALL
chronic weight loss & lymphadenopathy: CLL
diagnostic test for ALL
bone marrow biopsy with flow cytometry
therapy for ALL: describe drugs for each stage: induction, CNS therapy, intensification, maintenance
induction: prednisone, vincristine, doxorubicin, asparaginase, cyclophosphamide, dexamethasone
CNS therapy & intensification: chemo
maintenance: prednisone, methotrexate, mercaptupurine
state which drug (dexamethasone/prednisone, vincristine, doxorubicin, cyclophosphamide, asparaginase, methotrexate) is associated w/each MoA: A) directly toxic to lymphocytes B) folate antagonist C) alkylating agent inducing bulky DNA lesions D) inhibits microtubule polymerization E) depletes asparagine F) inhibits topoisomerase II
A) directly toxic to lymphocytes: prednisone/dexamethasone
B) folate antagonist: methotrexate
C) alkylating agent inducing bulky DNA lesions: cyclophosphamide
D) inhibits microtubule polymerization: vincristine E) depletes asparagine: asparaginase
F) inhibits topoisomerase II: doxorubicin
doxirubicin inhibits toperisomerase. what is topoisomerase?
topoisomerase II is an enzyme which relieves supercoil to allow for transcription. so inhibition of topoisomerase prevents uncoiling so the cells can’t transcribe and replicate
signs of DIC (labs)
increased PTT increased aPTT increased D-dimer decreased platelets decreased fibrinogen
clinical signs of DIC
petechiae, bruising, splinter hemorrhages, diaphoresis
what is tumor lysis syndrome? how does it present?
when tumor dies (from chemo or outgrowing blood supply, etc) cytokines and other cellular products are released. can lead to hypotension, AKI, labs: increased K+, → creatinine → uric acid, → phosphorous, → LDH, ↔ calcium
which of the following are associated with a better prognosis: t(9,22) Philadelphia chromosome, t(4,11), or hyperdiploidy
t(9,22) Philadelphia chromosome, t(4,11) are associated with poor prognosis
hyperdiploidy: better prognosis
what age group is most likely to have hyperdiploidy and therefore the best prognosis in ALL
children ages 1-10
which is more common: ALL or CLL
CLL is the most common form of leukemia
symptoms of CLL
chronic weight loss, lymphadenopathy, anemia (dizziness, fatigue), or asymptomatic
Describe stages 0-4 of CLL
Stage 0: monoclonal lymphocytosis
Stage 1: lymphadenopathy
Stage 2: hepatosplenomegaly
Stage 3: hemoglobin <100K
What is immune thrombocytopenic purpura?
An autoimmune disease characterized by IgG against platelet antigens. Antibody bound platelets are consumed in the spleen resulting in thrombocytopenia.
3 mechanisms of thrombocytopenia in CLL
splenic sequestration, ITP and marrow involvement
when do you treat CLL?
when it’s symptomatic (fever, night sweats, stage 3/4 CLL, rapid doubling time of WBC, systemic lymphadenopathy)
how does rituximab work?
monoclonal antibody to CD20
Idelalisib and Ibrutinib are newly approved therapies for CLL. in what patients are the most commonly prescribed? they are effective in CLL with what mutation?
used in relapse patients and 17p patients
are most tumors clonal or polyclonal?
most tumors are clonal. polyclonal tumors are rare.
can separate mutations act synergistically to produce a more malignant effect than each produces individually?
yup
what effect will c-MYc activation have on tumor cells?
c-myc activation will increase rate of division
are hMSH2 and hMLH1 genes typically activated or suppressed in cancer?
hMSH2 and hMLH1 are mismatch repair genes, commonly suppressed in cancer
what is a “proto-oncogene”? how is proto-oncogene activation different in the presence of a wildtype allele?
a gene which, when ACTIVATED, contributes to tumorgenesis, it is genetically dominant, in most cases, only one copy of the proto-oncogene need be activated, the presence of a wt copy will not reduce the phenotype
how are “dominant negative p53 mutations” an “Exception” to the rule?
usually p53 mutations act as tumor suppressor genes, where both copies need be deleted/defective to have loss of function, p53 is a homo tetramer, and a mutuation in just a single subunit will cause a dysfunctional protein
are most cancers heritable
no. 10% are heritable
describe how the age of onset, number of independent tumors and tumor frequencies changes depending on if the retinoblastoma was sporadic or inherited
age of onset: sporadic 6 years old, inherited 2 years old
number of independent tumors: sporadic = single tumor in one eye, heritable = multiple tumors with both eyes affected
are all carriers affected in sporadic and heritable retinoblastoma?
sporadic: both mutations acquired somatically, so if only one mutation, no effect
heritable: one alteration is germ line, all carriers will be affected with average of 10 tumors/person, both eyes affected
what cells are affected in Rb patients with abnormalities on chromosome 13? compare/contrast sporadic vs. heritable cases
sporadic cases: only tumor cells have chromosome 13 abnormalities
heritable cases: all cells have chromosome 13 abnormalities
do cases of sporadic Rb have mutations in the same gene as familial Rb?
yes
is there a risk of developing other (non-eye) tumors in Rb patients?
some carriers of germline Rb mutations will develop osteosarcomas, but this is very rare
explain how the phosphorylation state of Rb changes during the cell cycle. what phosphorylates Rb?
Rb is hypophosphorylated in G0 and early G1
Rb is hyperphosphorylated in S phase and G2 phase
CDK4/cyclin D is the complex which phosphorylates Rb
what is E2F? is it growth promoting or inhibiting?
E2F promotes S-phase genes, it is controlled by Rb (when Rb is unphosphorylated it binds to E2F and inhibits transcription of S phase products)
how could “occupancy of the Rb pocket” cause disease?
a virus (i.e. HPV) or other DNA virus protein can bind to the binding site on E2F, so that Rb can’t regulate it, this prevents Rb from being able to suppress transcription
what is p16? is p16 an oncogene or tumor suppressor?
p16 inhibits CDK4 (which deactivates Rb), it is a tumor suppressor
in retinoblastoma: is the Rb gene mutation dominant positive, dominant negative or recessive negative?
recessive negative (2 hits)
are p53 polypeptides more unstable when mutated or wildtype?
wildtype p53 polypeptides are more unstable
is MDM2 an oncoprotein or tumor suppressor? what effect does it have on p53?
oncoprotein, it inhibits p53
are p53 mutations common?
p53 mutations occur in most cancers
leukemia vs. lymphoma
leukemia: malignant lymphocytes in circulation, involvement of bone marrow
lymphoma: malignant transformation and proliferation in the lymph nodes
besides lymph nodes, what other parts of the body can be affected by lymphoma?Â
spleen can become enlarged, SVC syndrome (superior vena cava blockage), CSF involvement
presentation of someone with B cell lymphoma
lymphadenopathy, splenomegaly, anemia (fatigue), fever, weight loss, pruritis
what paraneoplastic syndromes can be seen in B cell lymphoma
nephrotic syndrome, hemolytic anemia, ITP
workup for someone with suspected B cell lymphoma: what imaging and labs would you order?
PET/CT to visualize lymphnodes
labs: LDH, Serum protein electrophoresis, CBC, ESR, lumbar puncture, test for viral infection
diagnosis of B cell lymphoma
excisional or core biopsy of hottest node, then workup: histologically, immunochemistry, cytogenetics, PCR, FISH
Stages of lymphoma: where is there involvement at each stage 1-4?
- 1 malignant cells confined to a single node
- 2 two or more lymph nodes are affected confined to one side of diaphragm
- 3 lymph nodes above and below diaphragm
- 4 multiple or disseminated foci of involvement
What criteria define one’s score (0-5) in IPI (international prognostic index) for B cell lymphoma?Â
Age (>60), serum LDH, ECOG status, Ann Arbor Stage, # of extra-nodal disease sites
What is the ECOG performance score 0-4? what does it attempt to gauge?
ECOG gauges how well a patient is feeling and how well they will potentially respond to treatment.
0 = fully active
1 = some symptoms
2 = Needs some assistance
3 = Needs complete assistance
4 = Near death
->ECOG3 - may not want to use chemotherapy because they may be too weak to handle it
what is the most common lymphoma?
diffuse large B-cell non-Hodgkin lymphoma
morphological characteristics of diffuse large B cell lymphoma
large lymphocytes 4-5x regular size
state which is a characteristic of Germinal Center B cell lymphoma or Non-Germinal center B cell lymphoma: 1)decreased suppression of NFKB 2) BCL6 dysregulation via silencing by p53
Germinal Center B cell Lymphoma: p53 silencing of BCL6
Non-GC B cell lymphoma: overactivation of NFKB
R-CHOP is a common treatment regiment for DLBCL. what is the mechanism of action for each of the R-CHOP drugs? R- rituximab C -cyclophosphamide H- hydroxyydanourubacin (doxorubicin) O -oncovin (vincristine) P - prednisone
R- rituximab: anti CD20
C -cyclophosphamide: alkylating agent
H- hydroxyydanourubacin (doxorubicin): topomerase II inhibitor
O -oncovin (vincristine): anti-microtubular
P - prednisone: direct toxicity to lymphocytes
why complication can sometimes arise with rituximab treatment since it is a human-mouse chimera? what additional complications can arise
allergic reaction, can be pre-treated with Tylenol/Benedryl, additional complications: tumor lysis syndrome, PML, reactivation of HBV, hypogammaglobulinemia