Transcript benign tumors

CHAPTER 7
NEOPLASIA
PRE LECTURE QUIZ (TRUE/FALSE)
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Cancer is a disorder of altered cell differentiation and
growth.
Surgery, radiation, and chemotherapy are the only
identified treatment modalities for cancer.
The Papanicolaou test is a cytologic method used to
detect cancer cells.
Cell differentiation is the process whereby proliferating
cells are transformed into different and more
specialized cell types.
Benign neoplasms are less differentiated tumors that
grow in a crablike manner to invade surrounding
tissues, have cells that break loose and travel to distant
sites to form metastases, and inevitably cause suffering
and death unless their growth can be controlled through
treatment.
PRE LECTURE QUIZ
grading
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The process of ______________ a tumor involves the
microscopic examination of cancer cells to determine
their level of differentiation and the number of
mitoses.
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In general, benign tumors usually are named by
adding the suffix __________ to the parenchymal
tissue type from which the growth originated.
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The term ________________ is used to describe the
development of a secondary tumor in a location
distant from the primary tumor.
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________________ spread would involve metastasis
that occurs by way of the blood vessels.
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________________ syndromes are defined as the
production of signs and symptoms at sites that are
not directly affected by the disease or cancer.
Hematogenic
Metastasis
-oma
Paraneoplastic
NEOPLASIA
Neoplasms proliferate to form new tissue
 They do not wait for signals from the
body that the new tissue is needed
 They ignore signals to stop dividing
 They often do not mature normally
(differentiate) to do the “job” the tissue is
supposed to do
 They do not die off (apoptosis) to keep
the number of total cells constant
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CANCER INCIDENCE AND MORTALITY
THE CELL CYCLE
Normally, the number of cells produced = the
number of cells that die
 The total number of cells in the body remains
constant
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GROWTH FACTORS
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Cells divide only when
they are told to do so by
growth factors
These cause stable
cells to enter the cell
cycle and divide
GROWTH FACTORS (CONT.)
Attach to receptor proteins 
 Which often work by affecting G proteins 
 Which turn on enzymes (proteins) 
 Which make second messengers 
 Which go down inside the cell and make it
divide
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GROWTH FACTOR RECEPTORS
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Now this cell is ready to
respond to growth factors
from another cell
They bind to the
receptors and stimulate
cell division
PROTO-ONCOGENES
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The normal genes that code for normal
proteins used in cell division
 Growth
factors
 Growth factor receptors
 G proteins
 Enzymes that produce second messengers
 Genes that turn the production of these
proteins on and off
ONCOGENES
Oncogenes are mutated proto-oncogenes
 They still code for the proteins needed for cell
division
 But they might produce
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 Too
much of the protein
 An abnormal protein
 Protein that turns on all by itself
 Protein that is made when it is not needed
 Protein that cannot turn cell division off
 Protein that should be made by a different cell
QUESTION
True or False:
Oncogenes code for normal proteins used in cell
division.
ANSWER
False
The statement describes proto-oncogenes.
Oncogenes are mutated proto-oncogenes that
code for abnormal proteins.
CHECKPOINTS IN CELL DIVISION
Permanent
cell
Cyclins make sure
the cell has made
the proteins needed
to separate the
chromosomes
M
G2
Cyclins check
that the DNA has
been correctly
duplicated
Cyclin
proteins
measure
whether the
cell has
grown large
enough to
divide
G0
Mitosis
G1
S
Interphase
R
TUMOR-SUPPRESSOR PROTEINS
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The checkpoints usually stop the division of mutated
cells
They keep most mutations from developing into
cancer
So the proteins that control the checkpoints are
called tumor-suppressor proteins
 Cyclins
 Cyclin-dependent kinases
 Cyclin inhibitors (p53)
If the genes for these proteins were mutated, you
might get many more cancers
CELL DIVISION REQUIRES DUPLICATING THE
DNA
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Telomeres: DNA sequences at the ends of
the chromosomes
 The
enzymes that duplicate DNA attach here
 The end of the telomere does not get
duplicated
 What will happen to the telomere as the cell
continues dividing?
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A man has a mutation that causes some of
his cells to rebuild their telomeres after
every division. Is this a good thing or a bad
thing? Why?
ONCOGENESIS
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Initiation: Initial mutation
occurs
Promotion: Mutated cells
are stimulated to divide
Progression: Tumor cells
compete with one
another and develop
more mutations which
make them more
aggressive
NORMAL CELLS
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Normally,
after a cell
has divided, it
becomes
either a
permanent
cell or a stable
cell
These cells
stop
reproducing
and continue
working for
the body
Labile = Apt or likely to change
M
Permanent
cell
G2
G1
S
G0
Stable cell
DIFFERENTIATION
• “Grown-up” cells are called differentiated because
they look different from one another
• You can tell a spleen cell from a skin cell
CELL MUTATION
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When differentiated, “working” cells mutate, they form
differentiated “working” tumors— benign tumors
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When undifferentiated, rapidly dividing cells mutate, they
form rapidly dividing tumors—malignant tumors
QUESTION
When a well-differentiated cell mutates, is it more
or less likely to become a malignant tumor?
a. More
b. Less
c. Degree of differentiation has no bearing on
whether a tumor is malignant or benign.
ANSWER
a.
Less
The more differentiated a cell is when it mutates,
the more likely it is to become a benign tumor.
If poorly differentiated cells mutate, the tumor
is more likely to become malignant.
NAMING TUMORS
• Benign tumors: tissue name + “-oma”
• Malignant tumors (cancers)
– Epithelial tissue: tissue name + “carcinoma”
– Mesenchymal tissue: tissue name + “sarcoma”
BENIGN TUMORS
Contain cells that look like normal tissue
cells
 May perform the normal function of the
tissue (like secreting hormones)
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This may lead to oversecretion
Usually have a capsule around them
 Usually do not invade neighboring tissues
 But they can damage nearby organs by
compressing them
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MALIGNANT TUMORS
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Contain cells that do not look like normal adult
cells
These cells divide rapidly, so:
 Tumors grow quickly
 Cells mutate faster and can change type
The tumor does not have clear boundaries and
sends “legs” out into surrounding tissue (the word
cancer means “crab” and is based on these
crablike legs)
Do not perform the normal functions of the organ
 May secrete hormones associated with other
tissues
Can compress and/or destroy the surrounding
tissues
METASTATIC CARCINOMA IN PERIAORTIC
LYMPH NODES
LUNG CANCER
QUESTION
What gross anatomic feature of the lung tumor
you just saw makes it likely to be malignant?
a. The tumor is growing quickly.
b. The tumor has a poorly defined border.
c. Cells do not look like normal cells.
d. All of the above
e. b and c
ANSWER
b and c
Gross anatomy can be viewed with the naked eye.
Although rapid growth is a characteristic
feature of malignant tumors, this cannot be
determined from the slide. However, the lack
of a clear border, and the different appearance
of the group of cancer cells can be clearly
seen.
e.
METASTASIS
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Cells in a primary tumor
develop the ability to
escape and travel in the
blood
Imagine you were a
cancer cell. What
abilities would you need
to survive in the tumor?
What abilities would you
need to metastasize?
SCENARIO
Mrs. T Has Liver Cancer
 Her doctor did an initial molecular diagnosis
and put her on targeted therapy; the tumor
shrank by almost 75%
 Two years later the tumor was growing again,
and this time it did not respond to the drug
 Last year she was diagnosed with metastases
in her femur that has not responded to the
drug either
 Mrs. T wants to know why the cancer cells
stopped responding. Are they not all the same
cells?
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MANIFESTATIONS OF CANCER
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Changes in organ function (organ damage,
inflammation, and failure)
Local effects of tumors (e.g., compression of nerves
or veins, gastrointestinal obstruction)
Ectopic hormones secreted by tumor cells
(paraneoplastic disorders)
Nonspecific signs of tissue breakdown (e.g., protein
wasting, bone breakdown)
CHANGES IN ORGAN FUNCTION
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Organ failure
Benign tumors may cause overproduction of normal
organ secretions
Malignant tumors may occasionally cause
overproduction (as in thyroid cancer), but more
commonly decrease production of normal organ
secretions
QUESTION
Why do malignant tumors usually cause a
reduction in the amount of hormones the
affected organ produces?
a. Organ damage
b. Inflammation of the organ
c. Organ failure
d. All of the above
e. a and c
ANSWER
All of the above
Effects of malignant tumors on the organ system
include inflammation and damage, which
ultimately lead to organ failure. In all cases
the organ cannot function optimally, and is
unable to secrete the normal/typical amount of
hormones.
d.
LOCAL EFFECTS OF TUMOR GROWTH
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Bleeding
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Compression of blood vessels
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Superior vena cava syndrome
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Portal hypertension
Compression of lymph vessels
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Edema, ascites, effusion
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Compression of hollow organs
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Compression of nerves
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Pain, paralysis
PARANEOPLASTIC SYNDROMES
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Cancer cells produce hormones or hormone-like proteins
 ADH
 ACTH
 PTH-related protein
Cancer cells produce proteins that affect clotting
Paraneoplastic neurologic disorders
CLINICAL MANIFESTATIONS OF CANCER
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Cancer cachexia syndrome
 Weight loss
 Muscle wasting
 Weakness
 Anorexia
 Anemia
TUMOR MARKERS
CANCER TREATMENT
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Surgery
Radiation Therapy
Chemotherapy
Hormone and
Antihormone Therapy
Biotherapy
INCIDENCE AND TYPES OF CHILDHOOD CANCER
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The incidence of childhood cancers is greatest
during the first years of life