24. Which of the following is WRONG concerning BRCA1 gene?
(A)BRCA1 gene is considered to be a tumor-suppressor gene.
(B)The wide-type BRCA1 allele protects against breast cancer.
(C)The mutant BRCA1 allele is recessive.
(D) The BRCA1 protein appears to function in the cell’s DNA damage repair pathway.
(E)A woman who inherits two mutant BRCA1 allele has a 60% probability of developing breast cancer before the age of 50.

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統計： A(7), B(13), C(42), D(16), E(65) #938819

生物生理生化分生

B1 · 2019/02/15

#3199847

A woman who inherits...

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面試倒楣鬼-22幸運上後西

B2 · 2022/04/15

#5418342

誰會去背這種數字= =

一粒塵埃

B3 · 2025/07/09

#6530249

BRCA1 是抑癌基因 (tumor-suppressor gene)，當基因完整時，能修復 DNA 損傷，預防突變累積。

若有 1 個突變拷貝，DNA 修復能力下降，乳癌風險上升 → 60% 的風險來自於「帶一個突變等位基因 (heterozygous)」。

兩個突變拷貝 (homozygous mutant) 的狀況通常「胚胎期致死」，不是 60% 風險，甚至活不下來。