Chapter 3: Neoplasia Flashcards
What are the three main characteristics of Neoplastic growth?
Neoplasia is new growth that is:
- ) Unregulated
- ) Irreversible
- ) Monoclonal in origin
Historically, which enzymes isoforms are used to test for monoclonal origin of neoplastic tissue ?
G6PD
Normally, there are two isoforms of G6PD in a human cell. What occurs in women ?
One is inactivated via X-inactivation. This creates a mosaic effect of G6PD expression
Normal ratio of G6PD isoforms
1:1
What is the ratio of G6PD isoforms seen in hyperplasia ?
1:1. It is maintained since hyperplasia is not monoclonal
What marker determines the clonality of B lymphocytes ?
Immunglobulin Light Chain (IgL)
What are the two main isoforms of IgL ?
Kappa and Lambda
In normal B-cells, what is the ratio of Kappa to Lambda IgL ?
3:1
What is the ratio of Kappa to Lambda IgL in hyperplasia ?
3:1 (it is maintained since it is monoclonal
What is the ratio of Kappa to Lambda IgL in neoplasia ?
Kappa increased : 6:1
Lambda Increased: 3:1
What are the two kinds of neoplasias in terms of staging ?
Benign
Malignant
Malignant tumors have a tendency to …
invade locally and possibly metastasize
Benign tumors…
remain localized and do not metastasize.
what type of tissues form carcinoma ?
Epitheliod tissues
What type of tissues form Sarcomas ?
Mesenchymal
benign lesions typically end in which suffix ?
-oma
What are two malignancies that end in -oma ?
Lymphoma, Melanoma.
Cancer is the _____ cause of death in adults and children.
2nd leading
What is the most common cause of death in adults ?
Cardiovascular Disease (followed by cancer and Chronic Respiratory Disease)
What is the most common cause of death in children ?
Accidents (followed by cancer and then congenital defects)
What are the three most common cancers in adults ?
- Breast/Prostate
- Lung
- Colorectal
What are the cancers which cause the most mortality in adults ?
- Lung
- Breast/Prostate
- Colorectal
Starting with a single mutated cell, how many divisions occur before the earliest signs of cancer occur ?
30
What is the goal of screening ?
- Finding dysplasia before it turns to neoplasia
2. Finding neoplasias that may turn malignant.
What does a Pap Smear detect ?
Cervical dysplasia
What does mammography detect ?
in situ breast cancer (has gone through the basement membrane but not to local lymph nodes)
PSA and Digital Rectal Exams detect ?
Prostate Carcinoma (usually clinically silent since it does not press on the urethra until late stage)
Hematocult test detects ?
Colonic carcinoma
What are the three major forms of Carcinogens ?
Chemical
Viral
Radiation
Protooncogenes are normal genes which stimulate…
Growth and differentiation
When mutated they lead to unregulated growth and differentiation. (usually some form of gain of function)
What are the 5 Major Classes of Proto-oncogenes ?
Growth Factors Growth Factor Receptors SIgnal Transducers Nuclear Regulators Cell Cycle Regulators
What is an important examples of Growth Factor proto-oncogenes ?
PDGFB (Platelet Derived Growth Factor Beta)
What tumor is associated with PDGFB ?
Astrocytoma
What mechanism occurs in PDGFB mutation that leads to neoplasia ?
Overexpression (Of PDGFB)
Which Growth Factor Receptor is mutated and associated with Breast Carcinoma ?
HER2/neu (Epithelial GFR)
aka Estrogen Receptor BB2 (ERBB2)
What mechanism occurs in HER2/neu mutation that leads to neoplasia ?
Amplification
When the Growth Factor Receptor RET undergoes POINT MUTATION, what tumor occurs ?
Medullary Thyroid Carcinoma (MTC)
Associated with:
MEN2A (MTC, Parathyroid hyperplasia, pheo.)
MEN2B (MTC, submucosal neoplasm, pheo)
RET (Neuronal GFR)
Gastrointestinal Stromal Tumors are associated with POINT MUTATION in which Growth Factor Receptor ?
KIT
Stem Cell GFR
Mutations in this Signal Transducer is seen in 70-80% of all cancers (carcinoma, melanoma, lymphoma) ?
RAS
What kind of mutations in RAS lead to neoplasm ?
Point Mutations
What kind of molecule is RAS associated with in its active state ?
GTP
RAS is a GTP binding protein (GDP bound = inactive)
Mutation often causes an inability to hydrolyze GTP to GDP
ABL is a signal transducer that is associated with which translocation seen in CML and Adult ALL ?
9:22 (Philadelphia Chromosome)
ABL is turned on by what kind of receptor complex ?
Tyrosine Kinase
In Burkitt Lymphoma, what translocation is responsible for a amplification of c-Myc ?
8:14
c-Myc is what kind of molecule ?
Nuclear Regulator (Transcription Factor)
Amplification fo N-myc (a transcription factor) leads to the formation of what cancer ?
Neuroblastoma
N= neuroblastoma
Amplification of L-Myc (a transcription factor) leads to the formation of what cancer ?
Small Cell LUNG carcinoma
L for Lung
Mantle Cell Lymphoma is caused by what translocation ?
11:14
What protooncogene is amplified in Mantle Cell Lymphoma due to the 11:14 translocation ?
Cyclin D (Cell Cycle Regulator)
Melanoma is associated with amplification of which Cell Cycle Regulator ?
Cyclin Dependent Kinase IV (CDK4)
What is found on chromosome 14 that allows for the amplification of c-Myc (Burkitts Lymphoma, 8:14) and cyclin D (Mantle Cell Lymphoma, 11:14) ?
The locus for the promoter of Immunoglobulin Heavy Chain
Burkitts and Mantle Cell are both B-Cell diseases. B-cells produce a lot of Ig. When the gene for c-Myc or Cyclin D are placed next to this promoter, their production is increased !