遗传学测试题：8-肿瘤遗传学

1、1. 癌基因在细胞水平呈（），一个等位基因的突变足以使正常细胞发生恶变。Ras蛋白是一个位于细胞膜内部，存在于细胞膜上信号转导蛋白。当它被细胞外因子激活时，便会从GDP状态变为有活性的GTP状态，产生刺激细胞生长的信号。而突变的Ras蛋白始终处于被激活的GTP活性状态。现已在许多肿瘤中发现了ras 基因的点突变。 (6.0分)A.不规则显性B.共显性C.中间显性D.显性E.延迟显性2. 尽管在大多数情况下，这些家族性肿瘤呈常染色体显性遗传，但其发生需要相应的肿瘤抑制基因的基因座上两个等位基因的（）。(6.0分)A.相互融合B.一个扩增C.全部扩增D.一个失活 E.全部失活3. Dar

2、a is a 40 year-old woman who has just been found to have breast cancer. Because of additional family history of breast cancer, her sisters are concerned that an inherited mutation is responsible for the cancer. A clinical geneticist discusses these concerns with the family and they decide to proceed

3、 with genetic testing. What type of sample would she get from Daras doctor to do this testing?(8.0分)A.Bone marrowB.White blood cellsC.Red blood cellsD.Biopsy of the tumor E.Cell line from the tumor4. Which of the following types of mutations would you expect to cause cancer when it occurs in an onco

4、gene?(8.0分)A.A or BB.A gain of function mutationC.Gene amplificationD.A loss of function mutationE.B or C5. Jill is concerned about her risk of hereditary breast cancer. Which of the following family histories would be most likely to be associated with a germline mutation that would predispose Jill

5、to breast cancer(If she inherited that mutation)?(8.0分)A.Breast cancer in Jill's paternal aunt at age 55 years and prostate cancer in her father at age 62 yearsB. Breast cancer in Jilil's mother at age 60 yearsC. Breast cancer in Jill's paternal grandmother at age 60 years and in her mat

6、ernal grandmother at age 62 years D. Breast cancer in Jill's paternal aunt at age 40 years and in her paternal grandmother at age 45 years E.Breast cancer in Jill's mother at age 60 years and prostate cancer in her father at age 62 years6. A 4-year old girl is seen by a dermatologist.The chi

7、ld has fair skin with many freckled areas and is very sensitive to light.She sunburns easily and does not like to play outdoors.Some of her freckled areas seem large and one is irritated.A defect in which DNA repair process is most likely the cause of her photosensitivity? (8.0分)A.Nucleotide excisio

8、n repair.B.Mismatch repair C.Non-homologous end joiningD.Base excision repairE.SOS repair7. A colonoscopy on a 20-year-old man reveals several hundred growths on the epithelial surface of the large bowel. Histologic examination of biopsied tissue revealed mild to moderate cellular dysplasia. DNA ana

9、lysis is most likely to reveal a mutation in which gene? (8.0分)A.RASB.DCCC.MLH1D.APCE.TP538. Jacks father and son were both affected by retinoblastoma when they were children, but Jack himself was not.Which of the following is the most likely explanation for the incomplete penetrance of the RB mutat

10、ion in Jack, who is an obligate carrier of the mutation? (8.0分)A.Jack carries a duplication of his wild-type copy of RBB.A spontaneous reversion of the RB mutation occurred early in Jacks developmentC.Jack inherited a second site mutation that counteracts the RB mutationD.No somatic mutation in RB o

11、ccurred in any of Jacks retinal cellsE.Jack carries a somatic deletion of the mutant RB allele9. Thus far, two genes have been found that can cause autosomal dominant breast cancer (one on chromosome 13 and one on chromosome 17).This is best described as an example of: (8.0分)A.Linkage disequili

12、briumB.Allelic heterogeneityC.SyntenyD.LinkageE.Locus heterogeneity10. Autosomal dominant breast cancer caused by mutations in the BRCA1 gene (chromosome 17) is characterized by:(8.0分)A.increased risk of small cell lung cancerB.increased incidence of breast cancer in malesC.increased risk of ovarian

13、 cancerD.relatively early age of onset of the diseaseE.A and C11. Which of the following is true of autosomal dominant breast cancer?(8.0分)A.Penetrance is close to 100%, with nearly all gene carriers developing breast cancer by age 80 B.It accounts for nearly half of all breast cancer cases in the U

14、nited StatesC.It can be detected by hybridization with a single oligonucleotide probeD.It is characterized by locus heterogeneityE.Autosomal dominant breast cancer affects females but not males12. Concerning retinoblastoma, which of the following is not predicted by the two-hit model? (8.0分)A.two copies of the gene must be disabled for tumor expression to occurB.inherited tumors will be multifocalC.penetrance is incompleteD.sporadic tumors will be unifocalE.imprinting will be observed13