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Questions and Answers
What distinguishes neoplasia from a tumor in medical terminology?
Which statement best defines hyperplasia?
What is the primary difference between hypertrophy and hyperplasia?
In which situation is metaplasia most likely to occur?
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What best describes a characteristic of both hypertrophy and hyperplasia?
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Which of the following accurately characterizes stem cells in adults?
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What occurs during the process of hypertrophy?
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Which condition is most likely to induce metaplasia in a tissue?
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What distinguishes neoplasia from hyperplasia and repair?
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Which feature is NOT typically associated with benign neoplasms?
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What is a defining characteristic of malignant neoplasms?
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What does it mean for a tumor to be classified as clonal?
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Which type of neoplasm is most likely to require complicated treatment due to its invasive nature?
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Which of the following statements is true regarding malignant tumors?
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What are the main features commonly found in benign neoplasms?
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Which statement regarding the growth characteristics of neoplasms is true?
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Which type of neoplasm is characterized by its ability to spread to distant sites?
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Which statement about basal cell carcinoma is correct?
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What characteristic is indicative of malignant cells compared to benign cells?
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What defines a teratoma?
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What is the primary purpose of cancer screening?
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Which of the following is NOT accounted for in the 'big 4' cancers responsible for approximately 50% of US cancer diagnoses and deaths?
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Which of the following is a key feature of dysplasia?
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Which suffix is typically associated with malignant epithelial neoplasms?
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What percentage risk of developing cancer do males have over their lifetime?
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Which of the following correctly describes a hamartoma?
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Which of the following cancers has the highest incidence in adults?
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Which cancer is the leading cause of cancer mortality in adults?
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What does a high nuclear/cytoplasmic ratio indicate in a cell?
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What trend has been observed in cancer death rates over the last 20-25 years?
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Which of these neoplasm types is specifically described as having a benign but highly differentiated nature?
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Which of the following factors has contributed to the decrease in cancer death rates?
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What term describes a neoplasm that occurs in a tissue where it is not normally found?
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How many million cases of basal cell carcinoma are diagnosed per year in the US?
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What percentage of total cancer cases are estimated to have a hereditary component?
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Which screening method is used specifically to detect changes before cervical cancer develops?
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What common environmental factor contributes to approximately 80% of lung cancer deaths?
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Which factor explains the higher risk of cancer due to the accumulation of genomic alterations?
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How does chronic inflammation increase the risk of cancer?
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Which of the following is the main cause of death from cancer in men aged 60-79?
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What percentage of cancer deaths is attributed to obesity?
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Which factor has a synergistic effect on increasing the risk of cancers in the upper aerodigestive tract?
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What is the result of DNA replication errors during stem cell division?
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Which of the following is linked to the increased risk of colorectal carcinoma?
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What is the primary infectious agent responsible for a significant number of cancer cases in developing countries?
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What reproductive factor significantly reduces the risk of breast cancer?
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Which cancer screening method is effective in detecting prostate carcinoma before it spreads?
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Which of the following cancers is not primarily associated with tobacco use?
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Study Notes
Neoplasia vs. Tumor
- Neoplasia literally means new growth.
- Tumor literally means swelling, is non-specific but often used synonymously with neoplasm.
- Not all new growth is neoplastic.
Not all new growth is neoplastic
- Wound repair and healing: granulation tissue
- Hyperplasia:
- Increase in the number of cells in an organ/tissue.
- Occurs in response to stimulus.
- Can be physiologic or pathologic.
- Ends when the stimulus is removed.
- Example: thickness of endometrium during the menstrual cycle.
- Hypertrophy:
- Increase in cell size.
- No cell division, no change in the number of cells.
- Increased production of proteins inside the cell
- Can be physiologic or pathologic.
- Example: muscle hypertrophy.
- Metaplasia:
- Reversible change in which one differentiated cell type is replaced by another.
- Almost always found in association with tissue damage/repair/regeneration.
- Typically replacing cell type better suited to alterations in the local environment.
- Underlying stem cells reprogrammed to differentiate along a new pathway.
- Stem cells: self-renewing cells present in all tissues that continue to divide.
- Example: Normal columnar cells of trachea/bronchi replaced by stratified squamous epithelium in smokers.
Neoplasia Definition
- Disorder of cell growth triggered by a series of genomic alterations.
- Excessive proliferation is independent of and uncontrolled by physiologic growth signals.
- Alterations give neoplastic cells a survival and growth advantage.
- Alterations affect a single cell and its clonal progeny.
Neoplasms: Benign and Malignant
- Benign neoplasms stay localized, do not spread/metastasize to other sites.
- Benign neoplasms are usually well-circumscribed and non-infiltrative.
- Benign neoplasms can often be removed surgically.
- Malignant neoplasms = cancer.
- Malignant neoplasms exhibit "invasive growth," destroying adjacent tissues.
- Malignant neoplasms can spread to distant sites (metastasize).
- Malignant neoplasm treatment is complicated, especially in advanced disease.
- Malignant neoplasm prognosis may be questionable.
Caveats for Benign and Malignant Neoplasms
- Benign neoplasms may behave aggressively, cause significant morbidity, or be fatal.
- Cancers may occasionally be quite small and require high levels of clinical skill to suspect and identify.
- Some cancers, like basal cell carcinoma, have low metastatic potential and can be treated quite simply/conservatively.
General (but not 100% reliable) features of Benign and Malignant Neoplasms
- Benign:
- Slow growth (months/years).
- Expansile (pushing) growth.
- Not metastasizing.
- Symmetrical, well-circumscribed.
- Nodular, pedunculated.
- Yellow, pink, blue.
- Less specific features: movable or fixed, firm or soft, can be ulcerated if traumatized, +/- pain.
- Malignant:
- Rapid growth (days/weeks).
- Invasive, destructive growth.
- Metastasizing.
- Asymmetrical.
- Exophytic.
- Black, brown, red.
- Less specific features: fixed, can be ulcerated with no hx of trauma, +/- pain.
Benign vs. Malignant: Microscopic Features
- Well-differentiated (resembling normal tissue) versus poorly-differentiated (not resembling normal tissue).
- Typical tissue organization versus atypical tissue structure.
- Rare, normal mitoses versus frequent, abnormal mitoses.
- Histologic features of malignancy:
- Pleomorphism: variable size and shape of cells/nuclei.
- High nuclear/cytoplasmic ratio of cells.
- Loss of identifiable differentiation.
Neoplasm Nomenclature
- Beginning of the name identifies tissue of origin.
- Myo- muscle:
- Leiomyo- smooth muscle.
- Rhabdomyo- skeletal muscle.
- Neuro/schwanno- neural tissue.
- Lipo- adipose tissue (= fat).
- Fibro- fibrous connective tissue.
- Angio- vessel:
- Hemangio- blood vessel.
- Lymphangio- lymph vessel.
- Myo- muscle:
- Ending of the name:
- oma = tumor.
- Usually means neoplasm.
- Usually benign.
- oma = tumor.
- Certainly Malignant:
- Carcinoma (epithelial malignancy).
- Adenocarcinoma- glandular features.
- Sarcoma (mesenchymal malignancy).
- Carcinoma (epithelial malignancy).
- Exceptions:
- Fibroma: not a neoplasm.
- Lymphoma: solid malignancy of lymphocytes.
- Leukemia: malignancy of peripheral blood.
- Melanoma: malignancy of melanocytes.
- Mesothelioma: malignancy of mesothelium.
Dysplasia
- Intraepithelial neoplasia: genetically altered cells stay within epithelium.
- Basement membrane acts as a barrier between epithelium and connective tissue.
- Dysplasia cannot grow aggressively or metastasize (yet).
- The patient can be cured by surgical excision.
- Dysplasia is a precursor to carcinoma.
- Once dysplasia invades through the basement membrane into connective tissue, it becomes carcinoma.
Carcinoma in Situ
- Dysplasia involving full thickness of epithelium, but still confined by basement membrane.
- The patient can still be cured by complete surgical excision.
Teratoma
- Benign tumor containing cells/tissues from more than one tissue type and more than one germ layer.
- Germ layers: endoderm, mesoderm, ectoderm.
- Nearly all other neoplasms consist of cells of one tissue type.
- Originates from germ cells.
- Totipotential stem cells normally present in testes and ovaries.
Hamartoma
- Benign proliferation of cells/tissues native to the involved site.
- Considered a benign, highly differentiated neoplasm.
Choristoma
- Benign proliferation of cells/tissues in a non-native site.
- Should not be there!
- Considered a benign, highly differentiated neoplasm.
Cancer Epidemiology
- 2nd leading cause of death in adults and children.
- Leading causes of death in adults: (1) cardiovascular disease, (2) cancer, (3) chronic respiratory disease.
- Leading causes of death in children: (1) accidents, (2) cancer, (3) congenital defects.
- Most common cancers by incidence in adults: (1) breast/prostate, (2) lung, (3) colorectal cancer.
- Most common causes of cancer mortality in adults: (1) lung, (2) breast/prostate, (3) colorectal.
Lifetime Cancer Risk
- Males:
- 40% risk of developing cancer.
- 21% risk of dying from cancer.
- Females:
- 39% risk of developing cancer.
- 18% risk of dying from cancer.
Cancer Incidence
- Approximately 50% of US cancer diagnoses/deaths are accounted for by the big 4: lung, breast, prostate, colorectal.
- Some cancers are more aggressive than others.
Basal Cell Carcinoma and Squamous Cell Carcinoma of the Skin
- Most common human cancers by far.
- BCC: 3-4 million cases per year in the US.
- SCC: 2-3 million cases per year in the US.
- Not included in cancer registries or epidemiology statistics.
- So much more common than other cancers that their inclusion would markedly skew statistics.
- A lot more indolent and treatable.
Cancer Death Rates
- In the last 20-25 years, overall cancer death rates have decreased.
- Changes in risk factors (e.g., smoking).
- Increased screening (e.g, Pap smears, mammograms, colonoscopies).
- Better therapy (e.g., immunotherapy, biologics, targeted therapy).
Cancer Screening
- Seeks to catch dysplasia (precancerous change) before it becomes carcinoma; or carcinoma before clinical symptoms arise.
- Purpose is to decrease cancer-specific mortality.
- Cancers that do not produce symptoms until late in the disease will have undergone additional divisions and, hence, additional mutations.
- Cancers that are detected late tend to have a poor prognosis.
- Common screening methods:
- Pap smear - detects cervical dysplasia (CIN) before it becomes carcinoma.
- Mammography - detects in situ breast cancer (e.g., DCIS) before it invades or invasive carcinoma before it becomes clinically palpable.
- Prostate-specific antigen (PSA) and digital rectal exam - detect prostate carcinoma before it spreads.
- Hemoccult test (for occult blood in stool) and colonoscopy - detect colonic adenoma before it becomes colonic carcinoma or carcinoma before it spreads.
Cancer and Age
- Most cancers occur over 55 years of age.
- Main cause of death in men aged 60-79.
- Main cause of death in women aged 40-79.
- Explained by:
- Accumulation of pathogenic genomic alterations in (stem) cells over a lifetime.
- Decline in immune system competence.
- Cancer accounts for 10% of all childhood deaths.
- 80% of childhood cancers are cured.
- Most common pediatric cancers are leukemia/lymphoma and brain/CNS tumors.
Carcinogenesis
- Results from the accumulation of complementary genomic alterations.
- These alterations must be accumulated in a stem cell (or a cell that acquires stem-like properties).
- Genomic (genetic and epigenetic) alterations come from three sources:
- DNA replication errors during (stem) cell division.
- Approximately 65-70% of mutations in human cancers.
- ~3 mutations and an unknown number of epigenetic alterations occur every time a normal human stem cell divides.
- Environmental factors.
- Inherited/hereditary genetic mutations.
- 5-10% of cancers have a hereditary component.
- DNA replication errors during (stem) cell division.
Stem Cells and Cancer
- Stem cells in different adult tissue types undergo different numbers of cell divisions.
- There is a strong correlation (0.8) between the average number of stem cell divisions per tissue and the rate/risk of cancer in that tissue.
Environmental Factors
- Remarkable geographic variation in cancer incidence provides evidence of the role of environmental carcinogens.
- Environmental influences appear to be dominant risk factors for many cancers.
- Approximately 20-40% of cancers may be preventable.
Environmental Carcinogens
- Tobacco:
- World's single greatest preventable cause of death.
- Single most important factor contributing to premature death in the US.
- Implicated in 80% of 140,000 annual lung cancer deaths.
- 4000-7000 deaths due to secondhand smoke.
- Also implicated in cancers of the oral cavity, pharynx, larynx, esophagus, pancreas, colon, and bladder.
- Obesity:
- Strongly associated with cancer risk.
- 10% of cancer deaths attributed to obesity.
- Linked with more than 10 cancers: colon, rectum, postmenopausal breast cancer, prostate.
- More than two-thirds of Americans are overweight/obese.
- 20% of children/adolescents are obese.
- Alcohol:
- Contributes to 5% of cancer deaths.
- Increased risk of cancers of: oral cavity, pharynx, larynx, esophagus, liver, colon, breast.
- Alcohol and tobacco synergistically increase the risk of cancers in the upper aerodigestive tract.
- Infectious agents:
- 15% of cancers worldwide.
- 30-45% of cancers in the developing world.
- Example: Many individuals infected with hepatitis C virus (HCV) may develop hepatocellular (liver) carcinoma.
- Human papillomavirus (HPV):
- Cause of cervical carcinoma.
- Cause of an increasing fraction of head and neck cancers.
- Oropharynx, in particular.
- Incidence of HPV-positive oropharyngeal cancer has now surpassed the incidence of cervical carcinoma.
- Reproductive history:
- Cumulative exposure to estrogen stimulation increases the risk of breast and endometrial cancer.
- Halves the risk of breast cancer with the age at first full-term pregnancy less than 20 years compared to more than 35 years.
- Postmenopausal hormone replacement therapy increases the risk of breast cancer.
- Other environmental carcinogens:
- In the environment: UV rays, smog.
- In the workplace: asbestos.
- In the diet: grilled meat, fat, alcohol.
Acquired Predisposing Conditions
- Chronic inflammation (infectious or non-infectious):
- Increased cell proliferation to repair damage --> increased opportunity for genetic mutations.
- Presence of activated immune cells in inflamed tissue produces reactive oxygen species that are directly genotoxic.
- Examples:
- Gastric reflux: increased risk of esophageal carcinoma.
- Alcoholism: increased risk of pancreatic carcinoma.
- Inflammatory bowel disease: increased risk of colorectal carcinoma.
- Autoimmune diseases (e.g., type 1 diabetes): increased risk of some cancers.
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Description
This quiz explores the concepts of neoplasia and tumors, highlighting their definitions, differences, and the various types of cell growth. Learn about hyperplasia, hypertrophy, and metaplasia, and understand how not all new growth is neoplastic. Gain insights into the physiological and pathological implications of these processes.