Neoplasia Flashcards
1
Q
H. pylori is implicated in the pathogenesis of what cancers?
A
Gastric adenocarcinoma
Gastric lymphomas
2
Q
How is the HTLV-1 retrovirus spread?
A
Sexually
Blood products
Breastfeeding
3
Q
Where are the two cell cycle checkpoints located?
A
Between G1 and S
Between G2 and M
4
Q
Define dysplasia
A
Disorderd growth
5
Q
Of the two general processes involved in cancer-associated hypercalcemia, which is considered to be paraneoplastic?
A
The production of calcemic humoral substances by extraosseous neoplasms
6
Q
A big differentiating factor between cancer and a benign tumor is that benign tumors do not metastasize to distant sites. What prevents a benign tumor from metastasizing?
A
They grow and expand slowly, allowing for the formation of a rim of fibrous tissue, a capsule, that separates them from the host tissue
7
Q
What is the purpose of grading a tumor?
A
To determine the extent to which the tumor cells resemble or fail to resemble their normal counterparts
8
Q
What cancers have the propensity for invasion of veins?
A
Hepatocellular carcinoma
Renal cell carcinoma
9
Q
What EBV genes help to promote carcinogenesis?
A
LMP-1
EBNA-2
vIL-10
10
Q
What determines whether a cell repairs its DNA, becomes senescent, or undergoes apoptos?
A
Duration and level of p53 activation
11
Q
There are different endocrinopathies that are classified as paraneoplastic syndromes, of these, which is the most common?
A
Cushing syndrome
12
Q
Tumor is now equated with neoplasm, what was tumor often used to describe in the past?
A
The swelling caused by inflammation
13
Q
What are the most common tumors that arise in men?
A
Prostate
Lung
Colon/rectum
14
Q
What cancers are in the immediate category of vulnerability to induction by radiation?
A
Breast, lung, salivary gland
15
Q
What cytokine is though to be involved in cachexia?
A
TNF
16
Q
What human retrovirus is implicated in the pathogenesis of cancer?
A
Human T-cell leukemia virus type 1 (HTLV-1)
17
Q
What are the high-risk strains of HPV?
A
16 and 18
18
Q
Hematogenous spread of cancer is more easily attained through the veins, as the vessel walls are thinner than those of arteries. Venous invasion allows the cells to flow from the site of the primary tumor, where do the cells typically come to rest?
A
In the first capillary bed they encounter, most commonly the lungs and the liver
19
Q
What chromosomal change is most commonly involved in the activation of proto-oncogenes?
A
Chromosomal translocation
20
Q
What tumor suppressor gene is the most frequently mutated gene in human cancers and has the main function of regulating cell cycle progression, DNA repair, cellular sensecence and apoptosis?
A
TP53
21
Q
What medical professional tends to grade a tumor?
A
Pathologist
22
Q
The growth and spread of a tumor is critically dependent on…
A
their stroma
23
Q
What cancer types often spread through the blood? (hematogenous spread)
A
Sarcomas
Sometimes carcinomas
24
Q
What are the common neoplasms of infancy and childhood that are not seen in adults
A
Small blue cell tumors:
Neuroblastoma
Wilms Tumor
Rhabdomyosarcoma
AML
Retinoblastoma
25
How do mixed tumors arise?
Divergent differentiation of a single neoplastic clone
26
Tumor differentiation is defined as
The extent to which neoplastic parenchymal cells resemble the corresponding normal parenchymal cells, both morphologically and functionally
27
The classification of a tumor and their behavior are determined by what component?
The tumor parenchyma
28
At what point does a carcinoma in situ turn into a carcinoma?
When the tumor cells breach the basement membrane
29
Mitoses are indicative of rapid cell growth, hence this is seen in normal tissues that rapidly turnover. What specific characteristics of mitoses are seen that would determine it to be part of a malignant neoplasm?
Atypical, bizarre mitotic figures, sometimes with tripolar, quadripolar or multipolar spindles
30
Most hematopoietic and solid tumors overexpress what protein, helping to evade apoptosis?
A member of the BCL2 family (BCL2, BCL-XL, MCL1)
31
Hypertrophic osteoarthropathy is characterized by
What cancers are associated with this paraneoplastic disorder?
Periosteal new bone formation, primarily at the distal end of long bones, hands/feet
Arthritis of adjacent joints
Clubbing of the digits
Bronchogenic carcinoma and thymic neoplasms
32
ERBB2 gene amplification is seen in what cancer type?
Breast carcinoma
33
What are the two classes of major cancer-associated mutations that affect the G1/S checkpoint?
Gain of function mutations in the D cyclin genes and CDK4 (promote progression)
Loss of function mutations in tumor suppressor genes (inhibit progression)
34
The main function of tumor suppressor genes is to apply the brakes on cell proliferation, what occurs when there are mutations in these tumor suppressor genes?
Failure of growth inhibition, another hallmark of cancer
35
What is the most common lung neoplasm associated with paraneoplastic hypercalcemia?
Squamous cell carcinoma
36
What enzyme is involved in a cancer cells evasion of the mitotic crisis?
Telomerase
37
What is a sentinel node and how is it used to clinically define the stage of a cancer?
The first node in a reginoal lymphatic basin that receives lymph flow from the primary tumor.
These nodes are used for biopsy to assess presence or absence of metastatic lesions in order to avoid the surgical morbidity associated with total lymph node ressection (lymphedema)
38
A mutation that contributes to the development of the malignant phenotype is referred to as
Driver mutation
39
Where is the WT1 gene located?
11p13
40
What is the most frequently mutated oncogenic pathway in human neoplasms?
Receptor tyrosine kinase pathway
41
ERBB1 point mutations are found in a subset of what cancers?
Lung adenocarcinomas
42
What type of mutations are a common early step in the malignant transformation of solid tumors?
Loss-of-function mutations
43
What growth factors are commonly expressed in a wide variety of tumor cells, promoting angiogenesis?
bFGF
VEGF
44
EBV is implicated in the pathogenesis of what tumors?
Of these, which is most common (bold the term)?
**Burkitt lymphoma (B-cell lymphoma)**
Subset of Hodgkin lymphoma
**Nasopharyngeal carcinoma**
Some gastric carcinomas
45
Cachexia is associated with
Equal loss of both fat and lean muscle
Elevated BMR
Evidence of systemic inflammation (increase in acute phase reactants)
46
What are the steps of tumor cell invasion
1. Dissociation of the cancer cells from one another
2. Degradation of the basement membrane and interstitial CT
3. Changes in attachment of tumors cells to ECM proteins
4. Locomotion
47
A malignant carcinoma is a tumor that originated from where?
Epithelial cells from any of the 3 germ layers (endoderm, mesoderm, ectoderm)
48
What chemical carcinogen is associated with a mutational hotspot?
What is it mean by hotspot?
aflatoxin B1
Some carcinogens interact preferentially with particular DNA sequences or bases, producing mutations that are clustered at "hotspots"
49
Two components of a tumor
1. neoplastic cells that constitute tumor parenchyma
2. reactive stroma made up of connective tissue, blood vessels, and variable numbers of cells of the adaptive and innate immune system
50
Translocation in mantle cell lymphoma
(11;14)(q13;q32)
51
Vinyl chloride, a refrigerant, is associated in the risk of developing what cancer?
Hepatic angiosarcoma
52
# Define metaplasia
Provide an example
Replacement of one cell type to another in response to stress, such that the new cell type is better suited to handle the stress
Barrets esophagus
53
Cancers associated with cushing syndrome
Small-cell carcinoma of the lung
Pancreatic carcinoma
Neural tumors
54
Mutation in WT1 leads to what familial syndrome and what sporadic cancer?
Familial Wilms tumor
Wilms tumor and certain leukemias
55
Lymphatic spread is the most common way for carcinomas to initially spread, how is this achieved if tumors to do have their own functional lymphatics?
Lymphatic vessels located adjacent to the site of the tumor are used to allow spread of neoplastic cells
56
Cancer is the main cause of death in men of what age group?
60-79
57
What are the molecular targets of chemical carcinogens?
DNA
58
Fine needle aspiration is a technique used to sample a lesion and assess the cells to determine grade of neoplasm, for what lesions is this method most commonly used?
Most commonly used for the assessment of easily palpable lesions such as the breast, thyroid, and lymph nodes
59
Solid tumor cells express what cell surface receptor that assists in their spread to lymph nodes and other sites?
CD44
60
What was the first tumor suppressor gene discovered, and functions as a prototype of genes of this type?
RB (retinoblastoma)
61
Anoikis is a form of cell death that results when what occurs?
When epithelial cells detach from the basement membranes
AND
from cell-cell interactions
62
What enzymes are required for the metabolic activation of an indirect-acting carcinogen into an active ultimate carcinogen?
cytochrome P450-dependent momo-oxygenases
63
alpha-fetoprotein is a tumor marker for what tumor types?
Liver cell CA
Nonseminomatous germ cell tumors of the testis
64
How does tax contribute to the acquisition of hallmarks of cancer?
Increases pro-growth signaling and cell survival
Increases genomic instability
65
Overexpression of what protein is linked to cancer cell survival and drug resistance (resistance to chemotherapy)
MCL1
(a member of the BCL-2 anti-apoptotic family)
66
Translocations in AML?
(8;21)(q22;q22)
| (15;17)(q22;q21)
67
Besides pancreatic adenocarcinomas and cholangiocarcinomas, what other cancer types can be attributed to mutations in RAS?
Colon, endometrial and thyroid cancers (50% of the time)
Lung adenocarcinomas, myeloid leukemias (30% of the time)
68
Translocation in follicular lymphoma
(14;18)(q32;q21)
69
Define oncogene
Mutated or overexpressed version of proto-oncogenes that function autonomously, having lost dependence on normal growth promoting signals
70
Salivary mixed tumors are often referred to as pleomorphic adenomas, what is characteristic of these tumors that attribute to this nomenclature?
These tumors arise from a single clone capable of producing both epithelial and myoepithelial cells
71
What cancers are caused by the HTLV-1 retrovirus?
Adult T-cell leukemia/lymphoma
72
Metastasis unequivocally marks a tumor as malignant and is defined by
the spread of tumor to sites that are physically discontinuous with the primary tumor
73
What is a hallmark of patients with mismatch-repair defects?
Microsatellite instability
74
What defines a paraneoplastic syndrome?
An individual with cancer has signs and symptoms that cannot be explained by the anatomic distribution of their tumor or by the elaboration of hormones indigenous to the tissue from which the tumor arose
75
Germline loss-of-function mutations in the E-cadherin gene, CDH1, result in what familial syndrome and what sporadic cancer?
Familial gastric carcinoma
Sportadic gastric carcinomas
76
What are the steps involved in chemical carcinogenesis and what do they involve?
_Initation_- cells are exposed to a carcinogenic agent, leading to cell alteration
_Promotion_- induce tumors to arise from initiated cells
77
Define neoplasia
New growth, often progressive and uncontrolled
78
All cancers have been found to display 8 fundamental changes in cell physiology, which are considered to be the hallmarks of cancer. What are these 8 hallmarks?
Self-sufficiency in growth signals
Insensitivity to growth-inhibitory signals
Altered cellular metabolism
Evasion of apoptosis
Limitless replicative potential (immortality)
Sustained angiogenesis
Ability to invade and metastasize
Ability to evade the host immune response
79
Tumors arising in the context of chronic inflammation are most likely of what type?
Carcinomas
80
What is the most common paraneoplastic syndrome?
Hypercalcemia
81
Describe the warburg effect
Despite ample oxygen, cancer cells exhibit a distinct for of cellular metabolism, consisting of high levels of glucose uptake and increased conversion of glucose to lactose
82
The rising incidence of cancer with age is explained by
accumulation of somatic mutations associated with the emergence of malignant neoplasms
83
Seeding of body cavities and surfaces by tumor cells occurs when
malignant neoplasias penetrate a natural open field, lacking physical barriers
84
Xeroderma pigmentosa arises 2/2 what type of mutation?
A mutation in nucleotide excision repair
85
Indirect-acting carcinogens
Require metabolic conversion in order to become active carcinogens
86
All initiating chemical carcinogens are
highly reactive electrophiles
87
Why are gastric lymphomas often termed MALTomas?
They are B-cell in origin and have some features of peyer's patches
88
The capsule formed around benign tumors make it easily excessible for surgical removal, why are malignant tumors difficult to surgical excise?
Most malignant tumors do not recognize normal anatomical boundaries and often penetrate walls of various organs. The invasiveness of these cancers make it difficult to resect them surgically
89
In what state is RB inactivated, thus allowing progression through the cell cycle?
Hyperphosphorylated
90
When looking at a histological image, when the term anaplastic is used, what is often seen?
Cellular and nuclear variation in size and shape. Prominant cells with abnormal mitotic spindles
91
Mutations in the NF2 gene result in neurofibromatosis type 2, those with this condition also develop what benign tumor?
What malignant tumor?
Benign bilateral schwannomas
Sporadic meningiomas, ependyomas
92
Mutation in the tumor suppressor gene RB leads to what familial syndrome and what sporadic cancers?
Retinoblastoma syndrome
Retinoblastoma, osteosarcoma, carcinomas of the breast colon and lung
93
What characterized adenomatous polyposis coli?
It is an autosomal dominant disorder in which individuals born with one mutant allele develop thousands of adenomatous polyps in the colon during their teens/20s, one or more of these polyps undergo malignant transformation
94
What are some examples of precursor lesions that can, but dont always, progress to cancer?
Barrett esophagus
Squamous metaplasia of bronchial mucosa
Colonic metaplasia
Endometrial hyperplasia
Leukoplakia
95
What 5 human DNA viruses have been implicated in the causation of cancer?
HPV
EBV
HBV
Merkel cell polyoma virus
HHSV8
96
how is a cystic teratoma of the ovary different from a mixed salivary tumor?
A salivary tumor contains epithelial components scattered with myxoid stroma of cartilage or bone
A cystic teratoma is of ectodermal origin, generating a cystic tumor lined with skin and hair, sebaceous glands and tooth structures
97
Carcinoembryonic antigen is a tumor marker for what tumor type?
Carcinomas of the colon, pancreas, lung, stomach, and heart
98
What is characteristic of nuclei in cancer cells?
Nuclei are disproportionately large for the cell
The shape is variable and often irregular
Chromatin are coarsely clumped a stain darker than normal
99
What 3 factors appear to be critical to the immortality of cancer cells?
Evasion of senscence
Evasion of mitotic crisis
Capacity for self-renewal
100
What is the main target of the HTLV-1 retrovirus?
CD4+ T-cells
101
Flow cytometry is often used to identify cellular antigens expressed by what tumor type?
"liquid" tumors- those that arise from blood-forming tissues
102
Staging of a solid tumor is based on
Size of the primary lesion
Its extent of spread to regional lymph nodes
Presence or absence of blood-borne metastases
103
A loss-of-function mutation in the WT1 gene is associated with the formation of what cancer type?
Wilms tumor
| (pediatric cancer of the kidneys)
104
Mutations in the proto-oncogene, ALK, lead to what associated human tumor
Lung adenocarcinoma
Some lymphomas
Neuroblastoma
105
In what ways can a tumor cell evade the immune system in an immunocompetent person?
Selective outgrowth of ag-negative variants
Loss or reduced expression of histocompatibility Ags
Immune suppression through the production of TGF-β, PD-1 ligand, and galectins by tumor cells
106
MLL2 is responsible for histone methylation, a mutation in this epigenomic regulatory gene results in what cancer type?
Follicular lymphoma
Frequency of mutation in this tumor type: 90%
107
Define oncoprotein
A protein encoded by an oncogene that drives increased cell proliferation through several mechanisms
108
Acanthosis nigricans is a disorder characterized by
Gray-black patches of thickened, hyperkeratotic skin with a velvety appearance
109
SNF5 is responsible for nucleosome positioning/chromatin remodeling, a mutation in this epigenomic regulatory gene results in what cancer type?
Malignant rhabdoid tumor
Frequency of mutation in this tumor type: 100%
110
Exposure to UV rays is associated with an increased risk of developing what types of cancers, particularly in fair skinned individuals?
Squamous cell carcinoma
Basal cell carcinoma
Melanoma
111
What cancers are frequently induced by radiation?
Myeloid leukemias
Thyroid cancer in young children
112
What three RAS genes are found in humans?
HRAS
KRAS
NRAS
113
Why are individuals with xeroderma pigmentosa at an increased risk of developing skin cancer, particularly after UV exposure?
UV light causes cross-linking of pyrimidine residues, these cross-links are typically repaired by the nucleotide excision repair pathway; however, patients with xeroderma pigmentosa lack this NER pathway and cannot uncross these linkages
114
What is responsible for the proteolysis of muscles, seen in cancer cachexia?
Humoral factors released from tumor cells
115
What gene encodes the p16 protein?
CDKN2A
116
Prostate-specific antigen is a tumor marker for what tumor type?
Prostate
117
When a neoplasm, whether it be benign or malignant, forms a visible projection above the mucosal surface, it is termed?
Where are these neoplasias often seen?
Polyp
in the stomach or colon
118
A loss-of-function mutation in what gene is associated with hereditary renal carcinomas, pheochromocytomas, hemangioblastomas, retinal angiomas and renal cysts?
VHL (Von Hippel Lindau)
119
Define proto-oncogene
normal cellular genes whose products promote cell proliferation
120
Cancer cells often display pleomorphism, what does this mean?
Cells vary in size and shape and thus cells within a tumor are not uniform
121
Malignant tumors arising from blood-forming cells, particularly white blood cells, are referred to as
Leukemias
122
What are the four regulatory genes that are the targets of cancer causing mutations?
Growth promoting proto-oncogenes
Growth inhibiting tumor suppressor genes
Genes that regulate programmed cell death (apoptosis)
Genes involved in DNA repair
123
Normal function of miRNA
They mediate sequence-specific inhibition of mRNA translation through RNA-induced silencing complex, controlling normal cell growth, differentiation, and cell survival
124
Direct-acting carcinogens
Provide an example
Require no metabolic conversions to become carcinogenic
Cancer chemo drugs
125
What in relation to cell adhesion is a key characteristic of carcinomas?
Loss-of-contact inhibition, by mutation of E-cadherin/β-catenin axis
126
Mutations in NF1 lead to what familial syndrome and what sporadic cancer?
Neurofibromatosis type 1
Neuroblastoma and juveline myeloid leukemia
127
What malignant neoplasms are inappropriately named by having benign terminologies
Lymph**oma**
Melan**oma**
Mesotheli**oma**
Semin**oma**
128
What contributes to the likelihood of a tumor metastasizing?
Lack of differentiation
Aggressive local invasion
Rapid growth
Large size
129
WT1 gene encodes for the protein WT1, what is the normal function of this protein?
Transcriptional activator of genes involved in renal and gonadal differentiation
130
In what ways is MYC thought to contribute to cancer cells?
MYC upregulates telomerase, contributing to cancer cell immortality
MYC acts with other TFs to reprogram somatic cells into pluripotent stem cells, contributing to cancer cell "stemness"
131
What pathway of apoptosis is most frequently disable in cancer?
Intrinsic
| (Mitochondrial)
132
What are the most common tumors that arise in women?
Breast
Lung
Colon/rectum
133
For what cancers is cytologic smears a common method employed to assess malignancy?
Carcinoma of the cervix
Endometrial carcinoma
Lung carcinoma
Bladder and prostatic tumors
Gastric carcinomas
134
What is the frequent cause of death of patients with adult T-cell leukemia/lymphoma?
Opportunistic infections
135
To designate a benign tumor from a malignant tumor, what suffix is added to the name?
-oma
136
Burkitt lymphoma is the most common childhood tumor in what areas of the world?
Central Africa
New Guinea
137
Malignant tumors that arise from solid mesenchymal tissues are referred to as
Sarcomas
138
The HTLV-1 genome contains the same genes as all retroviruses (*gag, pol, env, LTR)* but also contains what other gene?
*Tax,* which is essential for viral replication
139
Oncogenes are created by mutations in proto-oncogenes, what do proto-oncogenes encode?
proteins (oncoproteins) that have the ability to promote cell growth in the absence of normal growth-promoting signals
140
The molecular basis of multi-step carcinogenesis has been best defined through the evolution of what cancer?
Colorectal
141
Loss of normal cell control is central to malignant transformation, indicating at least one key regulators is dysregulated, what are the possible regulators that contribute to this malignant transformation?
p16/INK4a
Cyclin D
CDK4
RB
142
Mutations in the tumor suppressor gene TP53 result in what familial syndrome and what sporadic cancer?
Li-Fraumeni syndrome
Most human cancers
143
When is a neoplasm referred to carcinoma in situ?
When the dysplastic changes are marked and involve the full thickness of the epithelium, but does not penetrate the basement membrane
144
Chromothrypsis, also known as chromosome shattering, has been found in what types of cancers?
Osteosarcomas (25%)
Gliomas
145
Cancer is the main cause of death in women of what age group?
40-79
146
Immunodeficient states predispose to the development of what types of cancer?
virus-induced
147
In what state does RB exert antiproliferative effects?
Hypophosphorylated
148
Epithelial dysplasia is characterized by
A constellation of changes that include loss of uniformity of the cells as well as the loss in their architectural organization
149
Define adenoma
a benign epithelial neoplasm derived from glands, although they may or may not form glandular structures
150
What cancer type are HPV 16 and 18 implicated in?
Squamous cell carcinoma of the cervix, anogenital region, head and neck
151
What characterizes a tumor as benign?
The tumor is considered to be innocent; it will remain localized and will not spread to other sites, it is also amenable to local surgical removal
152
What was the first bacterium to be classified as a carcinogen?
H. pylori
153
Loss of function mutations in what gene is associated with familial adenomatous polyposis?
APC (adenomatous polyposis coli)
154
After metastasis, what is the most reliable feature that differentiates cancers from benign tumors?
Invasiveness
155
What cancers are associted with paraneoplastic hypercalcemia?
Carcinomas of the breast, lungs, kidneys, ovaries
156
Malignant tumors arising from lymphocytes and their precursors are referred to as
Lymphomas
157
Of the UV wavelengths, which is associated with the greatest risk of cancer development? Why?
UVB
Forms pyrimidine dimers in DNA
158
In what areas are adult T-cell leukemia/lymphomas caused the the HTLV-1 retrovirus commonly found?
Certain parts of Japan
Caribbean basin
South America
Africa
159
What is the most common pathway for the initial dissemination of carcinomas?
Lymphatic spread
160
What tumor suppressor gene is the "governer of proliferation" and is inactivated in most human cancers?
RB
161
Translocation in CML
(9;22)(q34;q11)
162
Mutations in the BCRA1 and BCRA2 genes lead to what familial syndrome and what sporadic cancers?
Familial breast and ovarian carcinoma, carcinomas of the male breast, chronic lymphocytic leukemia (BCRA2)
Sporadic cacners: Rare
163
Mutation in the tumor suppressor gene MSH results in what familial syndrome and what sporadic cancer?
Hereditary nonpolyposis colon carcinoma
Colon and endometrial carcinoma
164
Immunohistochemical identification of cytokeratins would indicate what type of cancer
Carcinoma (cells are of epithelial origin)
165
Hereditary nonpolyposis colon cancer syndrome is characterized by?
What does it result from?
Familial carcinomas of the colon, affecting the cecum and proximal colon
Results from defects in the genes encoding a group of proteins that work together to carry out DNA mismatch repair
166
PTCH1, a tumor suppressor gene, encodes the protein PATCHED1. This protein is a negative regulator of the Hedgehog signaling pathway.
A loss-of-function mutation in the PTCH1 gene results in uncontrolled hedgehog signaling, increasing the risk of developing what cancer types?
Basal cell carcinoma of the skin
Medulloblastoma
167
How do teratomas differ from other types of neoplasms?
Most neoplasms are derived from a single germ layer, while teratomas contain cells from more than one germ layer
168
According to the American Academy of Dermatology, what is the most common cancer in the US?
non-melanoma skin cancer
169
What are the major forms of underlying cancer in acanthosis nigricans?
Gastric carcinoma
Lung carcinoma
Uterine carcinoma
170
Why are individuals born with inherited defects in DNA repair mechanisms are at an increased risk for developing cancer?
The abnormalities that arise because of these defects enhances the occurrance of mutations in other genes during the process of normal cell division, which can lead to the development of cancers
171
NMYC gene amplification is seen in what cancer?
Neuroblastoma
172
Cachexia is characterized by
Progressive loss of body fat and lean body mass
Weakness
Anorexia
Anemia
173
What two oncofetal proteins serve as markers that aid in tumor diagnosis and clinical managment?
Carcinoembryonic Ag (CEA)
α-fetoprotein (AFP)
174
A mutation or translocation in the proto-oncogene BRAF results in what tumor type
Melanomas
Leukemias
Colon carcinoma
175
Translocation in Burkitt lymphoma
(8;14)(q24;q32)
176
What morphologic changes are often also seen with aplasia?
Pleomorphism
Abnormal nuclear morphology
Mitoses
Loss of polarity
177
How do mutations in RAS And PI3K contribute to cancer?
Oncogenic versions of these players lead to constitutive growth-factor independent tyrosine kinase activity
178
MLL1 is responsible for histone methylation, a mutation in this epigenomic regulatory gene results in what cancer type?
acute leukemia in infants
frequency of mutation in this tumor type: 90%
179
What is considered to be a hallmark of malignancy?
What does this term refer to?
Anaplasia
Lack of differentiation
180
HCG is a tumor marker for what tumor types?
Trophoblastic tumors
Nonseminoumatous testicular tumors
181
Even if a tumor has all the genetic aberrations require to undergo malignant transofmation, the tumor cell cannot grow unless it as the ability to induce what?
Angiogenesis
182
RAS point mutations are found in 90% of what cancer types?
## Footnote
**point mutations in the RAS family are the most common type of abnormality involving proto-oncogenes in human cancers**
Pancreatic adenocarcinomas
Cholangiocarcinomas
183
MYC translocations are seen in what types of cancer?
Burkitt lymphoma
184
What tissues are considered to be relatively resistant to radiation-induced neoplasia?
Skin
Bone
GI tract
185
immunohistochemical detection of desmin indicates a neoplasm of what origin?
Muscle
186
What are the two most important tumor suppressor genes that encode proteins that inhibit progression through the G1/S checkpoint?
RB
TP53
187
The metabolic conversion of an indirect-acting carcinogen forms a?
Provide an example
Ultimate carcinogen
Polycyclic hydrocarbons in fossil fuels
188
Generally, when does genomic instability occur?
When both copies of the DNA repair gene are lost
189
Describe the "two-hit" hypothesis of oncogenesis
\*described in the case of retinoblastoma\*
Two mutations, involving both alleles of RB, are required to produce retinoblastoma
Retinoblastoma develops when a child has one inherited defective copy of the allele, but the normal allele undergoes spontaneous mutation
In sporadic cases, both alleles must undergo somatic mutation for retinoblastoma to develop
190
70-85% of hepatocellular carcinomas are caused by an infection by what virus?
Hep B
OR
Hep C
191
What is ocogene addiction?
Certain tumor cells are highly dependent on the activity of one or more oncogenes
192
What medical professional determines the stage of a cancer?
An oncologist
193
Through what pathways is it possible for cancers to spread?
Direct seeding of body cavities or spaces
Lymphatic spread
Hematogenous spread
194
In what cancers is ABL gene translocated to another chromosome, where it fuses with the BCR gene, generating a constitutively active BCR-ABL tyroskine kinase?
Chronic myelogenous leukemia (CML)
Some acute lymphoblastic leukemias (ALL)
