Neoplasia Flashcards
Define neoplasia.
New growth - lack of responsiveness to normal growth controls
What is the study of neoplasms called?
Oncology
T/F: Benign neoplasms are often localized, slow growth.
TRUE
T/F: Benign tumors can move to other sites in the body.
FALSE
How can benign tumors cause serious problems for patients?
Can grow and put pressure on vital areas (ex. Major artery)
What is the most important differentiation between a benign and malignant cancer?
Malignant cancers can undergo METASTASIS
Can invade and destroy adjacent tissue
What is the difference between the parenchyma and the stroma?
Parenchyma: actual cancer cells making the tumor
Stroma: supporting connective tissue for the tumor
How are benign tumors named?
Type of parenchymal cell followed by -oma.
Ex. Fibroma, osteoma, etc.
What is a papilloma?
Benign tumor on surface epithelium with numerous finger-like projections
How are malignant tumors of mesenchymal tissue named?
Parenchymal tissue plus -sarcoma.
Ex. Fibrosarcoma, osteosarcoma, etc.
Describe the differences between a hamartoma and a choristoma?
Hamartoma: tissue normally found at the site
Choristoma: tissue not normally found at the anatomic site
A ____________ is a neoplasm derived from more than one germ layer.
Teratoma
What is the term for an epithelial malignant tumor?
Carcinoma
What are some various exceptions to nomenclature in malignant neoplasms?
- Lymphoma - lymph tissue
- Melanoma - melanocytes
- Mesothelioma - pleural
- Seminoma - testicular
T/F: Benign tumors have often lost their differentiation and do not resemble their tissue of origin.
FALSE
Benign are well-differentiated
T/F: Malignant tumors may have a wide range of differentiation.
TRUE
What is the term for a poorly-differentiated malignancy?
Anaplastic malignancy (high-grade)
What are some characteristics of anaplasia?
- Pleomorphism (odd size and shape)
- Nuclear hyperchromatism
- Atypical nuclei
- Odd mitotic patterns
__________ describes a tissue with disorderly growth, that although not cancerous, has the potential to become neoplastic.
Dysplasia
What is the most severe form of epithelial dysplasia?
Carcinoma-in-situ
T/F: If the cells of a tumor continue to show functional ability of the original cell-type, the cancer is more likely to be very severe.
FALSE
Functional ability means the cell is still well-differentiated.
Why might there be areas of necrosis in the center of a large malignancy?
It is growing so fast that it outgrows its blood supply
Many benign tumors have a __________, a compressed layer of connective tissue enclosing the tumor.
Capsule
What are two common benign neoplasms that do not have a capsule?
Hemangioma and neurofibroma
What is the most reliable feature in distinguishing malignant from benign tumors?
LOCAL INVASIVENESS
What is considered the hallmark of malignancy?
Metastasis
The process where malignancies invade nearby surrounding tissue is ___________; while the development of secondary deposits of a tumor at a distant site is __________.
Local invasions; metastasis
T/F: Basal cell carcinoma will rarely metastasize.
True
Approximately ___% of newly diagnosed patients with solid tumors will have metastases.
30%
What makes a tumor more likely to metastasize?
The larger and more anaplastic it is
What are the three ways which a neoplasm can metastasize?
- Seeding within body cavities
- Lymphatic spread
- Hematogenous spread
Which type of cancer spreads through both the blood and lymphatics?
Melanoma
Which types of cancers typically spread via the lymphatics? Via blood?
Lymphatics = carcinomas Blood = sarcomas
In 2017 there was how many deaths due to cancer?
600,000
What have been the trends of incidence in males and females over the last 50 years?
Increase in males but decrease in females. Most likely due to pap smears
Women have seen in increase in ______ cancer, but a decrease in _______ cancer over the last 40 years.
Lung; uterine
Approximately what proportion of cancer risk can be attributed to environmental factors?
2/3
Stomach cancer is much more common in Japan, while breast and prostate cancer is much more common in the U.S. What would the incidence trend be over several generations after a Japanese immigrant comes to the United States?
The incidence of stomach cancer would decrease, while the incidence of breast and prostate cancer would increase.
Because environment plays greater role than genetics
Between what ages does most cancer mortality occur?
Between 55-75
Cancer accounts for what percentage of deaths among children under 15 years of age?
10%
T/F: Cancer occurs in 1 out of every 5 people.
True
What are the three broad categories of genetic predisposition to cancer?
- Inherited cancer syndromes
- Familial cancers
- Defective DNA repair
What are some common inherited cancer syndromes?
- Retinoblastoma
- Familial adenomatous polyposis
- Multiple endocrine neoplasia
Inherited cancer syndromes are usually due to a ________ _____ mutation and generally show autosomal __________ transmission.
Single gene; dominant
T/F: Breast, colon, and ovarian cancers commonly run in families.
True
What percentage of all human cancers have an identifiable heritable basis?
5-10%
What is an acquired preneoplastic disorder?
A setup for cancer that is characterized by persistent regenerative cell replication.
What is the central molecular basis of all cancers?
Nonlethal genetic damage
What are the three classes of genes (and their functions) that are often affected in cancer cells?
- Protooncogenes: promote growth
- Cancer suppressor genes: inhibit growth
- Apoptosis genes: promote cell death
T/F: Most cancers are a result of a few genetically altered cells.
False
Most come from just one altered cell
What type of genes play an indirect role in the onset of carcinogenesis?
DNA repair genes
Carcinogenesis is a multi-step process both _________ and _________.
Phenotypically and genetically
What is the difference between a protooncogene and an oncogene?
Protooncogenes and oncogenes produce identical proteins except oncoproteins are NOT regulated
T/F: In carcinogenesis, protooncogenes are transformed to oncogenes.
TRUE
What are the two ways that oncogenes are activated?
- Structural mutation of the gene -> abnormal product
2. Altered regulation of gene expression -> increased production of normal product
What is the most commonly mutated proto-oncogene?
RAS
How does the mutant RAS differ from the normal RAS?
Cell continues to recieves signals to divide due to the inability for RAS to be deactivated properly
What is the most commonly affected nuclear transcription factor leading to carcinogenesis?
MYC gene
How does MYC mutation lead to carcinogenesis?
MYC gene is constantly overexpressed -> cell continuously dividing
What role do CDKs play in carcinogenesis?
CDKs play important role in determining if a cell will enter the cell cycle. Over-expression is seen in a variety of tumors.
While protooncogenes __________ cell growth, suppressor genes ________ cell proliferation.
stimulate; inhibit
What was the first tumor suppressor gene to be discovered?
Retinoblastoma (Rb)
Describe Knudson’s two-hit hypothesis for retinoblastoma.
For someone to develop Rb they inherit one mutated Rb allele, then the second must be mutated somatically.
Either way BOTH alleles must be mutated
T/F: The products of tumor suppressor genes are more well understood than those of protooncogenes.
False
T/F: Many of the tumor suppressor gene products regulate the cell cycle, cell adhesion, and signal transduction.
True
What is pRb’s role in regulating growth?
Binds transcription factors to regulate the cell-cycle
What gene is the single most common target for genetic alteration in human tumors?
TP53
T/F: The homozygous loss of TP53 is found in virtually every type of cancer.
True
What is Li-Fraumeni syndrome?
Being born with one mutated TP53 gene - higher risk of cancer
What is the role of normal TP53 products in the nucleus?
Slows the cell cycle during to allow time for the repair of DNA damage. If repair fails TP53 will trigger apoptosis
What would happen to a cell if TP53 was not functioning?
DNA damage would be incorporated into the DNA and the cell would continue to divide without undergoing apoptosis
What is the prototypic anti-apoptosis gene?
BCL2
The (over or under)expression of BCL2 protects cells from apoptosis?
Over-expression
T/F: A mutation in BCL2 will normally result in “high-grade” lymphomas.
FALSE
Slow growing so “low-grade”
What are the two major phases of metastasis?
- Invasion of extracellular matrix
2. Vascular dissemination and adhesion/homing of tumor cells
What is the process for tumor cells to invade the extracellular matrix?
- Tumor cells detach from each other
- Attach to ECM components
- Degradation of ECM components
- Migration
T/F: Tumor cells are in danger of being destroyed by host immune cells in the blood stream?
TRUE
How can one predict possible metasteses sites?
Follow the lymphatic and venous drainage from the original tumor site
What is organ tropism?
Tumor cells can only bind to specific sites when metastesizing
What is a familial disease that can lead to cancer of the colon that results from a defect in DNA mismatch repair and MSI?
Hereditary nonpolyposis colon cancer syndrome
__________ ___________ puts patients at higher risk for skin cancers due to an inability to repair UV damage.
Xeroderma pigmentosum
Bloom syndrome, ataxia telangiectasia, Fanconi anemia, and BRCA 1 & 2 breast cancers all cause _________ DNA.
fragile
T/F: Most cancers are the result of a single DNA mutation.
FALSE
Combo of several genetic alterations
What happens to the tumor cells as they continuously divide that could cause newer tumor cells to be more resistant to therapies?
As they divide they continue to develop more and more mutations
These severely mutated “subclones” are often selected for survival
Give an example of a balanced translocation that commonly leads to cancer.
Translocation between chromosome 22 and 9 - chronic myelogenous leukemia
What type of karyotypic changes often result Rb, colon, and oral cancer?
Deletions
Neuroblastomas and some breast cancers can be caused by this type of karyotypic change.
Gene amplifications
What are the three major classes of carcinogenic agents?
- Chemicals
- Radiation
- Virus
What was the first link between chemical carcinogens and cancer?
Sir Percival Pott linked chimney soot to scrotal skin cancer
T/F: Only synthetic compounds are capable of causing cancer.
FALSE
Both natural and synthetic chemical carcinogens
T/F: Most chemical carcinogens directly react with the nuclear DNA.
FALSE
Most are indirect - become active after metabolic conversion
In indirect chemical carcinogens, the ___________ is the original chemical, while the __________ is the active metabolite.
Procarcinogen; ultimate carcinogen
T/F: All chemical carcinogens are highly reactive electrophiles.
True
How long are latent periods between radiation exposure and cancer development?
7-12 years
Which RNA oncogenic virus is indemic in parts of Japan and the Caribbean basin?
Human T-cell Leukemia Virus Type I
How long is the latent period for T-cell Leukemia Virus Type I?
20-50 years
What are three common DNA oncogenic viruses?
HPV, EBV, and Hep B
What is the difference between tumor-specific antigens and tumor-associated antigens?
Specific: only associated with tumor cells
Associated: found on normal cells, but may be over-expressed in neoplastic cell
What are four antitumor effector mechanisms?
- Cytotoxic T cells: virus induced cancer
- NK cells: first line of defense
- Macrophages
- Humoral factors
What is the strongest evidence to show that the immune system plays a role in seeking out and destroying cancer cells?
Immunocompromised patients have a large increase in risk of developing cancer
How do tumors evade the immune system?
- Selection of antigen-negative subclones
- Reduced expression of histocombatible cells
- Lack of T-cell costimulation
- Immunosuppression
Adenomas and carcinomas arising from beta cells in the pancreatic islets may be fatal in what way?
Can cause altered hormone production and produce too much insulin
What needs to be worried about if a tumor expands to break through an epithelial surface?
Ulceration: bleeding and secondary infection
What is cachexia?
Progressive wasting involved with cancer
How many cancer patients will develop paraneoplastic syndromes?
10-15%
Hypercalcemia, Cushing’s syndrome, and paraneoplastic pemphigus are all examples of what?
Paraneoplastic disease
Grading attempts to assess the _____________ of cancer; staging describes the ____________ of cancer.
Aggressiveness; size and extent
T/F: Grade 1 cancer cells are more differentiated than grade 4.
True
Which is more important: staging or grading?
Staging
What is the TNM method for diagnosing squamous cell carcinoma?
T: primary tumor diameter
N: regional lymph node involvement
M: metastases
Which is quicker: frozen section biopsy or electron microscopy?
Frozen section biopsy
