po
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A 29-year-old woman feels a nodule in her neck. On examination there is a firm 2 cm mass in the right lobe of her thyroid. A fine needle aspiration shows cells consistent with papillary carcinoma. 2 years ago she had a lobular carcinoma excised from her left breast. Her 31-year-old sister was recently diagnosed with endometrial carcinoma. Over 3 generations, 16 of 24 close relatives have had a malignancy, most diagnosed before age 35. Which of the following most likely explains the increased risk for cancer in these people?
A Autosomal dominant cancer syndrome
B Defective DNA repair syndrome
C Germline mosaicism
D Multifactorial inheritance
E Teratogen
F Viral infection
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| SmokyWaters
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A .. 
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| SmokyWaters
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need to check with the answer...
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| po
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NOPE
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| SmokyWaters
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I was consdierin this as Li fraumeni syndrome... an autosomal dominant condition but when I read that many of the family members are involved...I changed my opinion...
defective DNA repair syndrome wud include HNPCC...
but it causes CA small intestine, endometrium, ovary alongwith colon... not this case
although its also an autosomal dominant condition..
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| silver
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is it B?
___________________
Everything turns out ok in the end. If it's not ok, then it's not the end.
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| SmokyWaters
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sorry its multifactorial inheritance
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| SmokyWaters
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I wrote the wrong letter.. :$
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| SmokyWaters
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D
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| po
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SmokyWaters wrote:
D
FINALLY? it is 
(D) CORRECT. Cancer that runs in families often does not have a clearly defined pattern of inheritance and does not have a specific genetic marker. Familial cancers should be suspected when cancers occur at a younger age, multiple family members are involved, and multiple sites are involved. The sites of involvement (breast, colon, thyroid, kidney, ovary) are similar to those for sporadic cancers.
(A) Incorrect. The pattern here is not that of the 50% recurrence risk for autosomal dominant conditions. Most autosomal dominant cancer syndroms involve one or two specific tissue sites.
(B) Incorrect. Most defective DNA repair syndromes are inherited in an autosomal recessive fashion and are rare. The most common is the hereditary non-polyposis colon cancer (HNPCC) syndrome, which involves colon.
(C) Incorrect. Germline mosaicism can account for a cluster of findings within siblings of a single generation. Cancer syndromes are generally not inherited in this fashion.
(E) Incorrect. Teratogens produce congenital anomalies via their effects upon the developing embryo. Cancers are unlikely to occur in this manner.
(F) Incorrect. Few viruses are associated with human malignancies. Some persistent viruses such as hepatitis B virus, may lead to precancerous conditions such as hepatic cirrhosis in which neoplasia is more likely to occur.
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