Neoplasia Chapter 7 Lecture (Putthoff) Flashcards
What causes Cancer?
Cancer is a complex group of diseases with many possible causes: genetics, tobacco, diet and physical activity, sun and UV exposure, radiation exposure and cancer, other carcinogens
How are different cancers alike?
In all cancers, cells grow out of control and spread into surrounding tissues
Cancer is a genetic disease? Does this mean it is inherited?
No, it means it is caused by changes to genes that control the way our cells function, especially how they grow and divide; acquired mutations over time, not necessarily inherited!
What is another cause of lung cancer that is not related to smoking? Which population is this type of lung cancer seen in?
Peripheral scar carcinoma also leads to lung cancer. Usually seen in older women. NOT caused by smoking!
How did cancer get its name?
Cancer usually has a spiculated, undefined border that looks like crab legs and “cancer” is crab in latin
Generic term for all malignant neoplasms?
Cancer
“new growth or form;” results from genetic alterations that are passed down to progeny of tumor cells. These genetic changes allow excessive and unregulated proliferation that becomes autonomous (independent of physiologic growth stimuli); occurs in a spectrum from benign to malignant
Neoplasia
_____ (swelling) was first used as one of the characteristics of acute inflammation. Now frequently used by physicians as a synonym for neoplasia
Tumor
Study of tumors (neoplasms); can be classified into medical, surgical, pediatric, etc
oncology
What is the term used to describe the fact that the entire population of a neoplasm arises from a single cell that has incurred genetic change
clonal
all neoplastic cells are clones of the original altered cell
Do cancers arise from de-differentiation of adult cells?
No! Adult cells do NOT go through metaplastic transformation; only primitive cells do! (aka basal cells?)
____ tumors are designated y attached the suffix -oma
benign
benign epithelial neoplasm derived from glands, although they may or may not form glandular structures
adenoma
benign epithelial neoplasms producing microscopically or macroscopically visible finger like or warty projections from epithelial surfaces
papillomas
Benign epithelial neoplasms that from cystic masses such as in the ovary? cystic masses and fibrous tissue?
cystadenoma
cystadenofibroma
A neoplasms is termed _____ when it can invade and destroy adjacent structures and spread to distant sites (metastasis) to cause death
malignant
Most types of cancers (85%) are ____
carcinomas, most are squamous cell carcinomas
Malignant neoplasms of epithelial cell origin, derived from any of the three germ layers are called _____
carcinomas
i.e, cancers from ectodermally derived epidermis, mesodermally derived renal tubules and endodermally derived lining of GI tract
Cancer in which tumor cells resemble stratified squamous epithelium
sqamous cell carcinoma (most common type)
Lesion in which the neoplastic epithelial cells grow in a glandular pattern.
adenocarcinoma
sometimes tissue or organ of origin can be identified and is added as descriptor like renal cell adenocarcinoma or bronchogenic sqamous cell carcinoma
cancer composed of cells of unknown tissue origin is designated as _____
undifferentiated malignant tumor
Malignant tumors arising in solid mesenchymal tissues are called _____
sarcomas
malignant tumors arising from blood forming cells are called ____
leukemias (white blood) or lymphomas (tumors of lymphocytes/precursors)
divergent differentiation of single neoplastic clone creates a ______
mixed tumor (like mixed tumor of salivary gland)
What things are found within a mixed tumor?
epithelial components scattered within a myxoid stroma that may contain islands of cartlage or bone.
In a mixed tumor, elements arise from a single clone capable of producing both epithelial and myoepithelial cells. This is called ______
pleiomorphic adenoma
Most mixed tumors are composed of cells from a single germ layer except what kind of mixed tumor?
teratoma
____ containns recognizable mature or immature cells or tissues belonging to more than one germ layer (sometimes all 3) because they arise from totipotential germ cells in ovary/testis
teratoma
Neoplasm which differentiates prinicpally along ectodermal lines to create a cystic tumor lined by skin replete with hair, sebaceous gland, and tooth structures
ovarian cystic teratoma (dermoid cyst)
Are teratomas and mixed tumors malignant or benign?
Mixed tumors are rarely malignant, teratomas also are benign
What are the two general components of tissue present in BOTH malignant AND benign neoplams?
Parenchyma and stroma
*classification of tumors based on parenchymal component but growth and spread dependent on stroma
_____ gives rise to neoplastic cellular component, is benign, malignant or other
parenchyma
___ is the supportive cellular component (tissue skeleton upon which the parenchymal component resides); generally not neoplastic (in carcinomals) and typically consists of connective tissue (supporting framework) and blood vessels (nutrition)
stroma
Does the stroma contain malignant cells?
No but may lead to thickness called desmoblastic reaction/desmoplasia??
*some desmoplastic tumors like in female breast are stony hard called scirrhous
polyp vs. adenoma in GI tract
When a neoplasm in the GI tract (benign or malignant) produces a macroscopically visible projection above a mucosal surface and projects into gastric or colonic lumen, it is called polyp; if it has glandular tissue it is called adenomatous polyp
Extent to which neoplastic parenchymal cells resemble the corresponding normal parenchymal cells, both morphologically and functionally
differentiation
- 2 major determinants of differentiation are:
1. neoplastic cells nuclei and cytoplasm and 2. architectural relationship of the neoplastic cells and non-neoplastic stroma
lack of differentiation is called _____ and is a hallmark of malignancy; means to form backward, implying a reversal of differntiation to a more primitive level
anaplasia
*The less differentiated a malignant neoplasm, the more aggressive its biologic behavior
Why are benign tumors generally considered well differentiated?
Because they closely resemble the normal cell type and mitoses are usually rare and are of normal configuration
example: neoplastic cells in a lipoma closely resemble normal adipocytes that makes it difficult to recognize the tumor by microscopic exam of individual cells; also leiomyoma of uterus resembles normal smooth muscle cells of myometrium; thyroid adenoma
While malignant neoplasms exhibit wide range of parenchymal cell differentiation, most exhibit morphologic alterations that betray their malignant nature. Exception?
Thyroid anemocarcinoma—form normal appearing follicles
some squamous cell carcinomas contain cells that appear identical to normal squamous epithelial cells
Grades of differentiation and clinical relevance?
Grade preceds second word in the phrase differentiated
- well differentiated: closely resembles parent tissue–thyroid carcinoma and some squamous cell carcinoma (like of the skin)
- moderately well differentiated: features of the original tissue type identifiable but not the dominant pattern, with additional atypia
- poorly differentiated: small minority of cellular constituents allow identification of the parent tissue; cellular anaplasia
- undifferentiated: tissue of origin cannot be discerned by histopathologic appearance of neoplasm; always associated with anaplasia
Morphological changes associated with anaplasia
Pleomorphism (different sized cells), abnormal nuclear morphology (nucleus to cytoplasm ratio increases–big nucleus), mitoses, loss of polarity (disorganized growth), other changes (ischemic necrosis)
Difference between metaplasia and dysplasia
metaplasia is replacment of one type of cell with another type; dysplasia literally means disordered growth
Evolution of dysplasia in sqamous epithelium (difference between CIS and carcinoma)
When dysplastic changes are marked and involve the full thickness of the epithelium but the lesion does NOT penetrate the basement membrane its called carcinoma in situ but once the tumor cells breach the basement membrane its is called an invasive tumor (carcinoma)
Does sqamous metaplasia begin in basilar cells or adult cells?
BASILAR CELLS!! Never from adult cells!
Differention in squamous cell carcinoma:
- Well differentiated tumor cells have prominent ____ production and ____ present
- Moderately differentiated has a much more ___ architecture
- Poorly differentiated has keratin present but what?
- keratin, intercellular bridges
- distorted
- keratin ONLY detected with special techniques
What kind of tumors (malignant or benign) retain the functions of the original cells of origin and which tumors sometimes acquire unexpected functions?
Benign retain function, malignant acquire unexpected functions due to derangements in differentiation
_____ tumors are slow growing; ____ tumors generally grow faster
benign, malignant
_____ tumors are poorly circumscribed and invade surrounding normal tissue; ___ tumors are circumscribed and may have a capsule
malignant, benign
Tumors of mesenchymal origin:
One parenchymal cell type
Benign: fibroma and lipoma
Malignant: fibrosarcoma and liposarcoma
Tumors of connective tissue and derivatives
One parenchymal cell type
Benign: chondroma and osteoma
Malignant: chondrosarcoma and osteoenic sarcoma
Tumors of vessels and surface coverings
One parenchymal cell type
blood vessels=hemangioma (B), angiosarcoma (M)
Lymph vessels=lymphangioma (b), lymphangiosarcoma (m)
mesothelium=benign fibrous tumor, mesothelioma (m)
Brain coverings=meningioma (B), invasive meningioma
tumors of blood cells and related cells
One parenchymal cell type
hematopoetic cells=leukemia (M)
Lymphoid tissue=lymphoma (M)
Tumors of muscle
One parenchymal cell type
smooth muscle: leiomyoma (B), leiomyosarcoma (M)
striated muscle: rhabdomyoma (B), Rhabdomyosarcoma (M)
Tumors of epithelial origin
stratified squamous
sqamous cell papilloma, squamous cell carcinoma
Tumors of epithelial origin
Basal cells of skin or adnexa
Basal cell carcinoma (malignant but never metastizes)
Tumors of epithelial origin
lining of glands or ducts
adenoma, adenocarcinoma
papilloma, papillary carcinomas (thyroid)
cystadenoma, cystadenocarcinoma (ovaries)
Tumors of epithelial origin
respiratory passages
bronchial adenoma, bronchogenic carcinoma
Tumors of epithelial origin
renal epithelium
renal tubular adenoma, renal cell carcinoma
Tumors of epithelial origin
liver cells
hepatic adenoma, hepatocellular carcinoma
Urinary tract epithelium (transitional)
transitional cell papilloma, transitional cell carcinoma
Placental epithelium
hydatidiform mole, choriocarcinoma
testicular epithelium (germ cells)
seminoma (malignant; no benign form)
Tumors of epithelial origin
tumors of malocytes
nevus, malignant melanoma
Mixed tumors–more than one neoplastic cell type but usually derived from ONE germ cell layer
salivary glands: pleomorphic adenoma aka mixed tumor of salivary origin (b), malignant mixed tumor of salivary gland origin (m)
renal anlage–wilms tumor (malignant)
Teratogenous–more than one neoplastic cell type derived from MORE than one germ layer–teratogenous
totipotential cells in gonads or embryonic rests: mature teratoma, dermoid cyst (b); immature teratoma, teratocarcinoma (m)
One unequivocal criterion of malignancy
metastasis–tumor to sites physically discontinuous with primary tumor; by definition benign neoplasms do NOT metastasize
How do cancers spread to discontinous areas?
the invasiveness of cancers permits them to penetrate blood vessels, lymphatics and body cavities providing opportunity for spread. All malignant tumors can metastasize but some do so very infreqently
Metastatic cascade:
- clonal expansion, growth, diversification angiogenesis
- Metastatic subclone
- Adhesion to and invasion of basement membrane
- passage through EC matrix
- Intravasation
- interaction with host lymphoid cells
- tumor cell embolus
- adhesion to basement membrane
- extravasation
- metastatic deposit
- angiogenesis
- growth
Sequence of events in the invasion of epithelial basement membranes by tumor cells
tumor cells detach from each other because of reduced adhesiveness and attract inflammatory cells. Proteases secreted from tumor cells and inflammatory cells degrade the basement membrane. Binding of tumor cells to proteolytically generated binding sites and tumor cell migration follow
Examples of cancers that invade early in their course but rarely metastasize
Gliomas (CNS) and basal cell carcinoma (skin)
Examples of metastatic malignancies of blood forming cells?
Trick question! Leukemias and lymphomas are systemic circulating malignancies so the term metastatic does NOT apply!
Cancers by incidence vs. cancers by diagnosis/death in US
Cancers by incidence: 1. prostate/breast 2. lung 3. colon
Cancers by diagnosis/death: 1. lung 2. prostate/breast 3. colon
Most common cancers in developing world
lung, stomach and liver in men; breat, cervix and lung in women
The incidence of cancer varies with geography, age, race, and genetic background. Cancers are the most common in people of what age? but occurs in adults and children of all ages. The geographic variation is due to what?
most common in adults older than 60
geographic variations due to different environmental exposures
Important environmental factors implicated in carcinogenesis:
infectious agents, smoking, alcohol, diet, obesity, reproductive history, and exposure to environmental carcinogens
what increases the risk of cancer?
reparative proliferations caused by chronic inflammation or tissue injury, certain forms of hyperplasia and immunodeficiency
Interactions between ____ and ___ may be important determinants of cancer risk
environmental factors and genetic factors
Smoking is not only associated with lung cancer but also with what other kind of cancer?
AML
Alcohol abuse is associated with what kind of cancer?
Hepatocellular carcinoma
Why is breast cancer risk in females that inherited BRCA1 and BRCA2 tumor suppressor genes 3x higher for women born after 1940?
Reproductive history changes—now women are having many more menstrual cycles because they are having less pregancies and having children later which means more opportunities for mutations during menstrual cycle
Name the type of cancers associated with the following agents:
- arsenic
- abestos
- benzene
- beryllium
- cadmium
- chromium
- nickel
- radon
- vinyl chloride
- lung carcinoma, skin carcinoma
- lung, esophageal, gastric, colon, mesothelioma
- AML
- Lung carcinoma
- prostate carcinoma
- lung and oropharyngeal carcinoma
- lung carcinoma
- hepatic angiosarcoma
Acquired predisposing conditions that are related to cancer
chronic inflammation
precursor lesions
immunodeficiency states
Cancer is the main cause of death among women aged 40-79 and men aged 60-79. why is the incidence of cancer higher with age?
accumulation of somatic mutations associated with emergence of malignant neoplasms
_____ are the most at risk for accumulating the genetic lesions that lead to carcinogenesis
proliferating cells
Tumors arising in the context of chronic inflammation are usually what kind of cancers?
Carcinomas but also include mesothelioma and several kinds of lymphoma
Immunodeficiency states tend to predispose to what kind of cancers?
Virus-induced cancers
Carcinomas, the most common general category of cancer in adults are extraordinarily RARE in ____
Children
When cancer occurs because of an inherited gene mutation, it is referred to as ______. Examples?
Heriditary cancer
Examples: mutations of BRCA1 and BRCA2 are inherited and substantially increase the risk of breast and ovarian cancer
By the time a tumor comes to clinical attention (1gm or 10^9 cells), it has gone through a minimum of ____ divisions
30
(Likely an underestimation since many cells die via apoptosis and due to Darwinian selection of the fittest for nutrients, etc)
The promiscuous tendency of tumors to become more aggressive over time due to selective pressure is called _______
Tumor progression
As a tumor cell population expands, a progressively ____ percent of tumor cells leave the replicating cellular pool
Higher
What does the tumor evolution of a renal carcinoma tell us?
The mutation constituency tends to vary from the original site and even varies between metastatic sites or locales
One of the most profound selective pressures that cancer cells face is ________
Chemotherapy or radiotherapy
*tumors that recur after therapy are almost always found to be resistant if the same treatment is given again because therapy selects for pre existent subclones that by change have a genotype that allow them to survive
Genomic themes in carcinogenesis:
Non lethal genetic damage
Clinal expansion of single precursor cell
4 classes of regulatory genes affected: growth promoting Porto-oncogenes, growth inhibiting tumor suppressor genes, genes that regulate apoptosis, and DNA repair genes
In epigenetic modifications what determines the lineage commitment and differentiation state of both normal and neoplastic cells?
DNA methylation and histone modification dictates which genes are expressed which in turn determines the lineage and differentiation
Cell and molecular hallmarks of cancer
Self-sufficiency in growth signals Insensitivity to growth-inhibitory signals Altered cellular metabolism Evasion of apoptosis Limitless replicative potential Sustained angiogenesis Ability to invade and metastasize Ability to evade host immune response