What is breast cancer?
Breast cancer is a disease in which certain
cells in the breast become abnormal and
multiply without control or order to form a
tumor. The most common form of breast
cancer begins in cells lining the ducts that
carry milk to the nipple (ductal cancer). Other
forms of breast cancer begin in the glands
that produce milk (lobular cancer) or in other
parts of the breast.
Early breast cancer usually does not cause
pain and may exhibit no noticeable
symptoms. As the cancer progresses, signs
and symptoms can include a lump or
thickening in or near the breast; a change in
the size or shape of the breast; nipple
discharge, tenderness, or retraction (turning
inward); and skin irritation, dimpling, or
scaliness. These changes can occur as part of
many different conditions, however. Having
one or more of these symptoms does not
mean that a person definitely has breast
cancer.
In some cases, cancerous tumors can invade
surrounding tissue and spread to other parts
of the body. If breast cancer spreads,
cancerous cells most often appear in the
bones, liver, lungs, or brain. Tumors that
begin at one site and then spread to other
areas of the body are called metastatic
cancers.
A small percentage of all breast cancers
cluster in families. Hereditary cancers are
those associated with inherited gene
mutations. Hereditary breast cancers tend to
occur earlier in life than noninherited
(sporadic) cases and are more likely to involve both breasts.
How common is breast cancer?
Researchers estimate that more than 178,000
new cases of invasive breast cancer will be
diagnosed in U.S. women in 2007. Most breast
cancers occur in women, but they can also
develop in men. Scientists estimate that more
than 2,000 new cases of breast cancer will be
diagnosed in men in 2007.
An estimated 5 percent to 10 percent of all
breast cancers are hereditary. Particular
mutations in genes associated with breast
cancer are more common among certain
geographic or ethnic groups, such as people of
Ashkenazi (central or eastern European)
Jewish heritage and people of Norwegian,
Icelandic, or Dutch ancestry. Particular
genetic changes occur more frequently in
these groups because they have a shared
ancestry over many generations.
What genes are related to breast cancer?
Variations of the BRCA1, BRCA2, CDH1, PTEN,
STK11, and TP53 genes increase the risk of
developing breast cancer.
The AR, ATM, BARD1, BRIP1, CHEK2, DIRAS3,
ERBB2, NBN, PALB2, RAD50, and RAD51
genes are associated with breast cancer.
Cancers occur when a buildup of genetic
mutations in critical genes—those that control
cell growth and division or the repair of
damaged DNA—allow cells to grow and divide
uncontrollably to form a tumor. In most
cases, these genetic changes are acquired
during a person's lifetime and are present
in certain cells. These changes, which are
called somatic mutations, are not inherited.
Less commonly, gene mutations inherited
from a parent increase the risk of developing
cancer. In people with these inherited genetic
changes, additional somatic mutations in
other genes must occur for cancer to develop
In addition to specific genetic changes,
researchers have identified many personal and
environmental factors that may influence a
person's risk of developing breast cancer.
These factors include gender, age, ethnic
background, a history of previous breast
cancer, certain changes in breast tissue, and
hormonal factors. A history of breast cancer in
closely related family members is also an
important risk factor, particularly if the cancer
occurred at an early age. Some breast cancers
that cluster in families are associated with
inherited mutations in particular genes, such
as BRCA1 or BRCA2.
BRCA1 and BRCA2 are major genes related to
hereditary breast cancer. Women who have
inherited certain mutations in these genes
have a high risk of developing breast cancer,
ovarian cancer, and several other types of
cancer during their lifetimes. Men with BRCA1
mutations also have an increased risk of
developing breast cancer. Additionally, BRCA1
mutations are associated with an increased
risk of pancreatic cancer. Mutations in the
BRCA2 gene are associated with an increased
chance of developing male breast cancer and
cancers of the prostate and pancreas. An
aggressive form of skin cancer called
melanoma is also more common among
people who have BRCA2 mutations.
Inherited changes in several other genes,
including CDH1, PTEN, STK11, and TP53, have
been found to increase the risk of developing
breast cancer. Mutations in these genes cause
syndromes that greatly increase the chance of
developing several types of cancer over a
person's lifetime. Some of these syndromes
also include other signs and symptoms, such
as the growth of noncancerous (benign)
tumors.
Some research suggests that inherited
variants of the ATM, BARD1, BRIP1, CHEK2,
NBN, PALB2, RAD50, and RAD51 genes, as
well as certain versions of the AR gene, may
also be associated with breast cancer risk. Not all studies have shown these connections,
however. Of these genes, ATM and CHEK2 have the strongest evidence of being related to the risk of developing breast cancer.
Noninherited (somatic) mutations also have
been identified in breast tumors. For example,
somatic mutations in the ERBB2 (also called
Her-2/neu), DIRAS3, and TP53 genes have
been associated with some cases of breast
cancer.
Read more about the AR, ATM, BARD1,
BRCA1, BRCA2, BRIP1, CDH1, CHEK2,
DIRAS3, ERBB2, NBN, PALB2, PTEN, RAD50,
RAD51, STK11, and TP53 genes.
How do people inherit breast cancer?
Most cases of breast cancer are not inherited.
These cancers are associated with genetic
changes that occur only in breast cancer cells
(somatic mutations) and occur during a
person's lifetime.
In hereditary breast cancer, the way that
cancer risk is inherited depends on the gene
involved. For example, mutations in the
BRCA1 and BRCA2 genes are inherited in an
autosomal dominant pattern, which means
one copy of the altered gene in each cell is
sufficient to increase a person's chance of
developing cancer. In other cases, the
inheritance of breast cancer risk is unclear. It
is important to note that people inherit an
increased risk of cancer, not the disease itself.
Not all people who inherit mutations in these
genes will develop cancer.
Where can I find information about treatment
for breast cancer?
These resources address the management of
breast cancer and may include treatment
providers.
- Gene Review: BRCA1 and BRCA2
- Hereditary Breast/Ovarian
Cancer 
- Genetic
Alliance
You might also find information on treatment
of breast cancer in Educational resources and
Patient support.
Where can I find additional information about
breast cancer?
You may find the following resources about
breast cancer helpful. These materials are
written for the general public.
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MedlinePlus - Health information (4 links)
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Additional NIH Resources - National
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Institutes of Health (6 links)
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Educational resources - Information pages
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(12 links)
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Patient support - For patients and families
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(10 links)
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MedlinePlus - Health information (4 links)
Additional NIH Resources - National
Institutes of Health (6 links)
Educational resources - Information pages
(12 links)
Patient support - For patients and families
(10 links)
You may also be interested in these resources, which are designed for healthcare
professionals and researchers.
- Gene
Reviews - Clinical summary -
Gene Tests - DNA tests ordered by
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healthcare professionals (3 links)
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- Genetic
Tools - Teaching cases ClinicalTrials.gov - Linking patients to medical researchPubMed - Recent literature- Online Books - Medical and science texts
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Bases of Inherited Disease
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(OMMBID):Breast
Cancer -
OMIM - Genetic disorder catalog
What other names do people use for breast
cancer?
- Breast cancer, familial
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- Breast carcinoma
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- Cancer of breast
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- Malignant neoplasm of breast
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- malignant tumor of breast
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- Mammary cancer
+ نوشته شده در جمعه دهم آبان ۱۳۸۷ ساعت 20:22 توسط dr
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I am P.h.D Student in Azerbaijan National Academy of Sciences.. My Search Subject the rule of ESR1 and ESR2 gene Mutations in Breast Tumorogeneis