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Old 01-17-2013
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Question Breast Cancer Gene Question

A 50-year-old woman saw her physician after noticing a mass in the right breast. Physical examination showed a 2-cm
mass fixed to the underlying tissues beneath the areola and three firm, nontender, lymph nodes palpable in the right axilla.
There was no family history of cancer. An excisional breast biopsy was performed, and microscopic examination showed a
well-differentiated ductal carcinoma. Over the next 6 months, additional lymph nodes became enlarged, and CT scans
showed nodules in the lung, liver, and brain. The patient died 9 months after diagnosis. Which of the following molecular
abnormalities is most likely to be found in this setting?
(A) Inactivation of one BRCA1 gene copy
(B) Deletion of one p53 gene copy
(C) Amplification of the ERBB2 (HER2) gene
(D) Deletion of an RB gene locus
(E) Fusion of BCR and C-ABL genes
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Old 01-17-2013
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erb b2 oncogene; rest r tumor suppressor genes and her 2 neu overexpression is associated with poor prognosis;
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Old 01-17-2013
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ans. c) amplification of the ERBS2 (HER2) gene.
It is seems to be INVASIVE DUCTAL carcinoma.

while options (A and b): familial cases mostly associated with BRACA1 OR P53. but in this case no family history.
waiting for answr
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Old 01-17-2013
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Quote:
Originally Posted by tyagee View Post
A 50-year-old woman saw her physician after noticing a mass in the right breast. Physical examination showed a 2-cm
mass fixed to the underlying tissues beneath the areola and three firm, nontender, lymph nodes palpable in the right axilla.
There was no family history of cancer. An excisional breast biopsy was performed, and microscopic examination showed a
well-differentiated ductal carcinoma. Over the next 6 months, additional lymph nodes became enlarged, and CT scans
showed nodules in the lung, liver, and brain. The patient died 9 months after diagnosis. Which of the following molecular
abnormalities is most likely to be found in this setting?
(A) Inactivation of one BRCA1 gene copy
(B) Deletion of one p53 gene copy
(C) Amplification of the ERBB2 (HER2) gene
(D) Deletion of an RB gene locus
(E) Fusion of BCR and C-ABL genes
A) is not the answer because the question clearly states that the patient has no history of breast cancer in her family (although there are rare cases of sporadic BRAC1 mutation, normally BRAC1+2 are inherited in an AD manner. The questions I've seen with this gene mutation will tell you that the daughter's mother or aunt died of breast cancer for example).

B) With p53 mutations, you get all kinds of solid tumors through out the body (Li-Fraumeni syndrome). The question does say that they found nodule in her lung and brain but those are likely due to metastasis and not primary tumors.

D) If an RB gene is completely mutated in a patient (both copies that is), they will have retinoblastoma as children and during their adolescent years bone cancer and later possibly breast cancer.

E) has nothing to do with breast cancer (CLL)

That leaves option C. The more amplified the gene (i.e. the more ERBB copies you have, the worst the prognosis which in this case is very evident as it has already metastasized and she died).
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Old 01-17-2013
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Its breast cancer type. So we will narrow the answer choices to A and C. Next we will look at family history. In this case there's none; so choice A will be out. The answer will be C.


If there is family history then the answer will be A.
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Old 01-18-2013
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Quote:
Originally Posted by Doctor Ali View Post
Its breast cancer type. So we will narrow the answer choices to A and C. Next we will look at family history. In this case there's none; so choice A will be out. The answer will be C.


If there is family history then the answer will be A.
wow, correct reasoning. ans is C! thanks all above members for posting.
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Old 07-13-2015
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Default two hit rule

the explanations was very informative and in addition: i think i remember that P53 and Rb tumor suppressor genes, follow "two-hit" rule, meaning that two copy of them should be mutated to predispose the patient to various cancers.if one copy is mutated, the tumor suppressor protein still will be intact(because the mutations in these genes are recessive).
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Old 08-11-2015
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Generally, in breast biopsy the samples are study in pathology under the microscope that gives an accurate diagnosis to manage patientís care. Breast carcinomas are categorize into two main types such as ductal and lobular. HER2 gene amplification has become very important in choosing the best treatment for early and advanced breast cancer stage. So according to your question, the answer is C.
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Old 02-03-2016
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http://cancerpreventionresearch.aacr...nt/3/1/12.full

even BRCA follows the knudson's 2 hit hypothesis.
Strengthens C being the most likely answer.
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