cancer
a disorder of altered cell differentiation and growth
proliferation- cell division to replace cells
differentiation- specialization where the new cells acquire the structural, microscopic, and functional characteristics of the cells they replace
neoplasia
the resulting process from cancer is called neoplasia, meaning new growth, and the new growth is called a neoplasm
-unlike the process of hypertrophy and hyperplasia, the cell changes that occur with neoplasia tend to be relatively uncoordinated and auton
benign neoplasms
-well differentiated but lost control of cell proliferation
-benign neoplasms are well differentiated tumors that resemble the tissues of origin but have lost the ability to control cell proliferation. They grow by expansion, are enclosed in a fibrous cap
malignant neoplasms
less differentiated and lost the ability to control both proliferation and differentiation
-malignant neoplasms are less well differentiated tumors that have lost the ability to control both cell proliferation and differentiation. they grow in a disorgani
cancers are commonly referred to as
tumors or neoplasms
how are benign tumors named
usually named by adding the suffix oma to the parenchymal tissue typre from which the growth originated
ex. adenoma, fibroma
how are malignant tumors named
the term carcinoma is used to designate a malignant tumor of epithelial tissue origin ex.adenocarcinoma
malignant tumors of mesenchymal origin are called sarcomas ex. fibrosarcoma
the cell cycle
normally, the number of cell produced = the number of cell that die off
the total number of cells in the body remains constant
-cancer cells are autonomous (unregulated, uncontrolled do what they want)
state at least four ways that benign and melignant neoplasms differ
1. the characteristics of the tumor cells
2. the rate of growth
3. local invasion
4. the ability to metastasize
growth factors
cells divide only when they are told to do so by growth factors
-these cause stable cells to enter the cell cycle and divide
-attach to receptor proteins
-which often work by affecting G proteins
-which turn on enzymes (proteins)
-which make second messen
trace the pathway for hematologic spread of a metastic cancer cell
-lungs and liver are the most frequent metastic sites for hematologic spread since venous blood from the gastrointestinal tract, pancreas, and spleen is routed through the portal vein to the liver, and all vena caval blood flows to the lungs
To metastasiz
growth fraction
the ratio of dividing cells to resting cells in a tissue mass
doubling time
the length of time it takes for a total mass of cells in a tumor to double
-cancer cells continue to divide until limitations in blood supply and nutrients inhibit their growth
-one of the reasons cancerous tumors often seem to grown so rapidly relates to
proto- oncogenes
the normal genes that code for normal proteins used in cell division
-associated with gene over activity (genes that turn the production of these proteins on and off)
-encode for normal cell proteins such as growth factors, growth factor receptors, growth
tumor supressor genes
the category of cancer associated with underactivity genes includes the tumor supressor genes, which, by being less active, create an environment in which cancer is promoted
oncogenes
mutated proto-oncogenes
they still code for the proteins needed for cell division but they might produce:
-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 t
tumor supressor proteins
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
if the
epigenetic mechanisms
involve changes in the patterns of gene expression with out a change in the DNA
epigenetic mechanisms may silence genes, such as tumor supressor genes so that even though the gene is present it is not expressed and a cancer suppressing protein is not made
anaplasia
used to describe the loss of cell differentiation in cancerous tissue
state the importance of angiogenesis in cancer growth and metastasis
once in a distant site, the process of metastatic tumor development depends on the establishment of blood vesses and specific growth factors that promote proliferation of the tumor cells
tumor cells as well as other cells in the microenvironment secrete a
how is heredity related to cancer
several characteristics exhibit an autosomal dominant inheritance patters that greatly increases the risk of developing a tumor.
-the inherited mutation is usually a point mutation occuring in a single allele of a tumor suppressor gene
two tumor supressor
how are levels of endogenous hormones related to cancer
hormones have recieved considerable research attention with respect to cancer of the breast, ovary, and endometrium in women and of the prostate and testis in men
although the link between hormones and the development of cancer is unclear, it has been sug
how is obesity related to cancer
the process relating obesity to cancer development is multifactorial and involves a network of metabolic and immunologic mechanisms
obesity has been associated with insulin resistance and increased production of pancreatic insulin, both of which have a ca
how is immune system function related to cancer
the immune system plays a central role in resistance against the development of tumors.
it has been suggested that the development of cancer might be associated with impairment or decline in the surveillance capacity of the immune system
for example, incr
viral and microbial agents
an oncogenic virus is one that can induce cancer
only four DNA viruses have been implicated in human cancers
-the human papilloma virus (HPV), epstein-barr virus (EBV), hepatitis B virus (HBV), and human herpesvirus 8 (HHV-8)
define and describe cancer cachexia
many cancers are associated with weight loss and wasting of body fat and muscle tissue, accompanied by profound weakness, anorexia, and anemia
this wasting syndrome is often referred to as the cancer anorexia-cachexia syndrome
it is common manifestation o
define the term paraneoplastic syndrome
in addition to signs and symptoms at the sites of primary and metastic disease, cancer can produce manifestations in sites that are not directly affected by the disease.
such manifestations are collectively referred to as paraneoplastic syndrome
some of t
papanicolaou test
the pap test is a cytologic method that is used for detecting cancer cells. it consists of a microscopic examination of a properly prepare slide by for the purpose of detecting the presence of abnormal cells
tissue biopsy
involves the removal of a tissue specimen for microscopic study
tumor markers
antigens expressed on the surface of tumor cells or substances released from normal cells in response to the presence of tumor
two basic methods for classifying cancer
grading according to the histologic or cellular characteristics of the tumor and staging according to the clinical spread of the disease
grading
grading of tumors involves the microscopic examination of cancer cells to determine their level of differentiation and the number of mitoses. the closer the tumor cells resemble comparable normal tissue cells, both morphologically and functionally, the lo
staging
the clinical staging of cancers uses methods to determine the extent and spread of the disease. it is useful in determining the choice of treatment for individual patients, estimating prognosis, and comparing the results of different treatment regimens. t
explain the mechanism by which radiation exerts its beneficial effects in the treatment of cancer
radiation exerts its effects through ionizing radiation, which affects cells by direct ionization of molecules or, more commonly, by indirect ionization. it can immediately kill cells, delay or halt cell cycle progression, or at dose levels commonly used
describe the adverse effects of radiation
to some extent, however, radiation is injurious to all rapidly dividing proliferating cells, including those of the bone marrow and the mucosal lining of the gastrointestinal tract. this results in many common adverse effects including infection, bleeding
cancer chemotherapy drugs may be classified as either
cell cycle specific or cell cycle nonspecific
cell cycle specific chemotherapeutic drugs
drugs are cell cycle specific if they exert their action during a specific phase of the cell cycle
cell cycle non specific chemotherapeutic drugs
drugs that extert their effects throughout all phases of the cell cycle
biotherapy
involves the use of immunotherapy and biologic response modifiers as a means of changing the persons immune response to cancer
three mechanisms by which biotherapy exerts its effects:
modification of host responses
modification of tumor cell biology
immun
cite the early warning signs of cancer in children
usually involve the hematopoietic system, nervous system, soft tissues, bone, and kidneys
often characterized by sheets of cells, with small round nuclei, and frequently exhibit features of organogenesis specific to the site of origin
-the incidence of ch
discuss the possible concerns of adult survivors of childhood cancer
impaired growth, neurologic dysfunction, hormonal dysfunction, cardiomyopathy, pulmonary fibrosis, and risk for second malignancies
genetic screening
scren for individuals at risk due to a family history of some neoplasms
-BRRCA gene mutation in either BRCA-1 or BRCA-2
-harmful mutations in these genes produce a hereditary breat-ovarian cancer syndrome in affected families
-five to ten percent of all b
checkpoints in cell division
cyclins make sure the cell has made the proteins needed to seperate the chromosomes
cyclins check that the DNA has been correctly duplicated
oncogenesis
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
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
differentiation
grown up" cells are called differentiated because they look different from one another
you can tell a spleen cell from a skin cell
anaplasia- poorly differentiated or undifferentiated cells
The TNM staging system
the T category describes the original (primary) tumor measured in centimeters
-the number T1, T2, T3, and T4 describe the tumor size. The higher the T number, the larger the tumor.
The N category describes spread into nearby lymph nodes
-N0 means nearby l
cell mutation
when differentiated, "working" cells mutate, they form differentiated "working" tumors - benign tumors
when undifferentiated, rapidly dividing cells mutate, they form rapidly dividing tumors- malignant tumors
when a well differntiatied cell mutates, is it more or less likely to become a malignant tumor
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
manifestations of cancer
changes in organ function (organ damage, inflammation, and failure)
-local effects of tumors (compression of nerves, or veins, gastrointestinal obstruction)
ectopic hormones secreted by tumor cells (paraneoplastic disorders)
-nonspecific signs of tissue b
changes in organ function
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
why do malignant tumors usually cause a reduction in the amount of hormones the affected organ produces
organ damage, inflammation of the organ, organ failure
local effects of tumor growth
-bleeding
-compression of blood vessels
superior vena cava syndrome
portal hypertension
-compression of lymph vessels
edema, ascites, effusion
-compression of hollow organs
-compression of nerves
pain, paralysis