Molecular diagnostic-Molecular Diagnostics

Question 1

1. Which method is most useful for confirmation
   that a culture isolate is Group B streptococcus?
   A. Southern blotting
   B. Polymerase chain reaction
   C. Direct hybridization
   D. Probe capture assay

Answer 1

C. Direct hybridization

Question 2

2. In situ hybridization (ISH) tests for human
   papilloma virus (HPV) using cervical smears
   differ from immunochemical staining of tissue in
   which regard?
   A. ISH has lower analytical sensitivity
   B. ISH has lower analytical specificity
   C. ISH differentiates subtypes more easily
   D. ISH differentiates cervical neoplasia from
   genital warts

Answer 2

C. ISH differentiates subtypes more easily

Question 3

3. Which method is most sensitive for detection of
   viral meningitis?
   A. Viral culture
   B. CSF WBC count
   C. Specific antibody testing of CSF for viral
   antigens
   D. Real-time RT-PCR

Answer 3

D. Real-time RT-PCR

Question 4

4. What gene must be amplified in PCR to
   differentiate methicillin-resistant Staphylococcus
   aureus from methicillin-resistant coagulase-negative
   Staphylococcus?
   A. orfX
   B. mecA
   C. VanA
   D. iles-2

Answer 4

A. orfX

Question 5

5. Which statement best describes real-time PCR
   testing for Mycobacterium tuberculosis?
   A. The test is positive only in cases of smear-positive
   and culture-positive infections
   B. The test has a sensitivity of > 99% on all
   specimen types when compared to culture
   C. The test can detect 85%–90% of smear-negative,
   culture-positive infections
   D. The test sensitivity is near 100% but specificity is
   approximately 80%

Answer 5

C. The test can detect 85%–90% of smear-negative,

Question 6

6. How can cell proliferation be explained by the
   BCR/ABL gene rearrangement that occurs in
   the 9:22 translocation that causes the Ph1
   chromosome of CML?
   A. It causes underexpression of p53
   B. A hybrid protein is made that up-regulates the
   cell cycle
   C. Translocation induces a point mutation in the
   ABL oncogene
   D. ABL activates p23

Answer 6

B. A hybrid protein is made that up-regulates the
cell cycle

Question 7

7. Which statement accurately describes the clinical
   utility of translocation testing in leukemia?
   A. Relapse is predicted by any new translocation
   occurring after treatment
   B. Specific translocations associated with a type
   of leukemia will occur in all cases
   C. Translocation products for each leukemia
   subtype are always the same
   D. Translocation is a sensitive way to identify
   surviving leukemic cells following treatment

Answer 7

D. Translocation is a sensitive way to identify
surviving leukemic cells following treatment

Question 8

8. Which is the most sensitive method of minimal
   residual disease testing in chronic myelogenous
   leukemia?
   A. Karyotyping analysis
   B. FISH
   C. Flow cytometry
   D. RT-PCR

Answer 8

D. RT-PCR

Question 9

9. How can cell proliferation be explained by the
   BCL 2 translocation t(14;18) that occurs in
   up to 90% of persons with follicular B-cell
   lymphoma?
   A. p53 is underexpressed
   B. A hybrid protein is made that up-regulates the
   cell cycle
   C. Transcription of the BCL 2 oncogene is
   increased by the translocation
   D. The BCL 2 gene joins with the p21 gene,
   making it inactive

Answer 9

C. Transcription of the BCL 2 oncogene is
increased by the translocation

Question 10

10. Which mechanism is responsible for
    retinoblastoma?
    A. Mutation of a tumor suppressor gene
    B. Mutation of a tyrosine kinase gene
    C. Activation of an oncogene
    D. Deletion of a gene encoding a GTPase
    activator

Answer 10

A. Mutation of a tumor suppressor gene

Question 11

11. Which oncogene is involved in the etiology of
    Burkitt’s lymphoma?
    A. ABL
    B. Myc
    C. Ras
    D. HER/neu

Answer 11

B. Myc

Question 12

12. The majority of cases of Duchenne’s muscular
    dystrophy are caused by which type of genetic
    damage?
    A. Point mutation
    B. Insertion
    C. Deletion
    D. Trinucleotide repeats

Answer 12

C. Deletion

Question 13

13. How are cases of Duchenne’s muscular dystrophy
    not detected by PCR usually confirmed?
    A. DNA sequencing
    B. Linkage analysis
    C. Macroarray analysis
    D. Dystrophin protein staining

Answer 13

B. Linkage analysis

Question 14

14. Inheritance of BRCA1 or BRCA2 mutations
    increases the risk of breast and ovarian cancer
    by which mechanism?
    A. Oncogene production
    B. Transcription signaling by the mutant protein
    C. Deficient tumor suppressor function
    D. Chimeric protein production

Answer 14

C. Deficient tumor suppressor function

Question 15

15. Polymorphisms of the cytochrome p450 genes
    are important in identifying which condition?
    A. Poor drug metabolism
    B. Risk for primary biliary cirrhosis
    C. Progression of hepatitis C to hepatic cirrhosis
    D. Parentage in cases where HLA results are
    inconclusive

Answer 15

A. Poor drug metabolism

Question 16

16. Approximately how may mutations have been
    identified in the gene coding for the cystic fibrosis
    trans membrane conductor regulator protein
    (CFTR)?
    A. 10
    B. 100
    C. 1,000
    D. 10,000

Answer 16

C. 1,000

Question 17

17. Which statement about CF is accurate?
    A. A sweat chloride test is abnormal in all forms
    of CF
    B. Immunoreactive trypsin is deficient in all persons
    with CF
    C. Some CF mutations can cause male infertility
    with no other symptoms
    D. The CF genotype always predicts the severity of
    the disease

Answer 17

C. Some CF mutations can cause male infertility

Question 18

18. Which of the following alleles has the highest
    frequency in the general population?
    A. ΔF508 (cystic fibrosis)
    B. Factor V-Leiden (hereditary thrombophilia)
    C. Prothrombin G20210A (hereditary
    thrombophilia)
    D. Methylene tetrahydrofolate reductase mutation
    C677T homocysteinemia

Answer 18

D. Methylene tetrahydrofolate reductase mutation
C677T homocysteinemia

Question 19

19. HLA typing can be done by which molecular
    method?
    A. PCR analysis using 96 well microtrays with allele
    or groups specific primers in each
    B. Restriction fragment length polymorphism
    testing
    C. Direct hybridization with WBCs on a peripheral
    blood film
    D. Fluorescent in situ hybridization reactions with
    peripheral blood lymphocytes

Answer 19

A. PCR analysis using 96 well microtrays with allele
or groups specific primers in each

Question 20

20. Which statement best describes the relationship
    between HLA DNA typing and serological
    haplotypes?
    A. One or two bands are seen for each locus
    correlating to reactivity with a specific antigen or
    group of antigens
    B. HLA alleles cannot be related to HLA antigens
    because antisera specificity is unrelated to genetic
    polymorphism
    C. A single antibody specificity always corresponds
    to a single allele
    D. Not all HLA genes produce antigens recognized
    by antibodies

Answer 20

A. One or two bands are seen for each locus
correlating to reactivity with a specific antigen or
group of antigens

Question 21

21. Highest-resolution HLA typing is needed for
    which of the following transplants?
    A. Heart
    B. Liver
    C. Kidney
    D. Bone marrow

Answer 21

D. Bone marrow

Question 22

22. Which method of DNA analysis is used most often
    to detect the hemoglobin S gene?
    A. FISH
    B. PCR followed by RFLP
    C. Cytogenetic analysis of chromosome 11
    D. Labeled probe painting of chromosome 11

Answer 22

B. PCR followed by RFLP

Question 23

23. Which of the following genetic diseases is caused
    by an expanded trinucleotide repeat?
    A. Prader–Willi syndrome
    B. Angelman’s syndrome
    C. Fragile X syndrome
    D. Williams’ syndrome

Answer 23

C. Fragile X syndrome

Question 24

24. Which is the most common method used for
    parentage testing in the United States?
    A. Short tandem repeat analysis
    B. Nuclear DNA sequencing
    C. HLA DNA typing
    D. Mitochondrial DNA sequencing

Answer 24

A. Short tandem repeat analysis

Question 25

25. In order to prove exclusion in DNA paternity
    testing, why must two genes be identified that
    must come from the biological father and
    did not?
    A. A single exclusion can result from laboratory
    error
    B. A single exclusion can result from germ line
    mutation within one locus being tested
    C. The biological father may be a blood relative to
    the alleged father
    D. The biological mother may be different than the
    purported mother

Answer 25

B. A single exclusion can result from germ line
mutation within one locus being tested

Question 26

26. Hereditary hemochromatosis is the result of which
    type of mutation?
    A. Nonsense mutation
    B. Microdeletion
    C. Translocation
    D. Single nucleotide substitution

Answer 26

D. Single nucleotide substitution

Question 27

27. p21 is a GTP binding protein produced by which
    oncogene?
    A. RET
    B. Ras
    C. HER-2/neu
    D. N-Myc

Answer 27

B. Ras

Question 28

28. Which of the following thalassemias can be
    detected by PCR followed by blotting with
    a single specific oligonucleotide probe?
    A. α-Thalassemia
    B. Hemoglobin S/β-thalassemia
    C. β-Thalassemia
    D. Hemoglobin S/β-thalassemia

Answer 28

A. α-Thalassemia

Question 29

29. Which method is used to determine if the
    hemoglobin C gene is present in fetal cells?
    A. Chromosome painting
    B. FISH
    C. Restriction enzyme analysis
    D. PCR followed by blotting with a specific
    oligonucleotide probe

Answer 29

D. PCR followed by blotting with a specific
oligonucleotide probe

Question 30

30. In flow cytometry, the term “gating” refers to:
    A. Selection of a subpopulation of cells to count
    B. Determining the fluorescent emission spectrum
    of cells of interest
    C. Interference caused by binding of more than a
    single antibody
    D. Selecting the appropriate counting aperture

Answer 30

A. Selection of a subpopulation of cells to count

Question 31

31. Which of the following parameters are used to gate
    cells processed by the flow cytometer?
    A. Font surface fluorescence versus incident laser
    intensity
    B. Forward light scatter versus side scatter
    C. The ratio of light emitted at two different
    wavelengths
    D. Impedance amplitude versus background
    conductance

Answer 31

B. Forward light scatter versus side scatter

Question 32

32. In general, which statement best characterizes the
    relationship between white blood cells and light
    scattering in flow cytometry?
    A. Forward scatter is related to cell size and side
    scatter to granularity
    B. Forward scatter is related to nuclear density and
    side scatter to size
    C. Forward scatter is inversely related to size and
    side scatter is directly related to size
    D. Forward scatter

Answer 32

A. Forward scatter is related to cell size and side
scatter to granularity

Question 33

33. Fluorescent dyes most commonly conjugated to
    antibodies used in flow cytometry are:
    A. Fluorescein isothiocyanate and Texas red
    B. Calcofluor white and Texas red
    C. Phycoerythrin and fluorescein isothiocyanate
    D. Acridine orange and rhodamine

Answer 33

C. Phycoerythrin and fluorescein isothiocyanate

Question 34

34. A cell population is positive for surface markers
    CD45, CD3, CD4, and Tdt. Which type of
    leukocytes are these?
    A. Lymphocytes
    B. Granulocytes
    C. Monocytes
    D. Early myeloid precursors

Answer 34

A. Lymphocytes

Question 35

35. A FISH test is performed on a slide of peripheral
    blood leukocytes. The test uses a dual fusion
    probe, consisting of a Spectrum Green labeled
    probe to the BCR 22 q11.2 locus, and a Spectrum
    Orange labeled probe to ABL 9q34. What disease
    is this test for?
    A. Chronic myelogenous leukemia
    B. Multiple myeloma
    C. Bladder cancer
    D. Thyroid cancer

Answer 35

A. Chronic myelogenous leukemia

Question 36

36. A tissue sample for DNA analysis by PCR
    was processed for DNA by simple lysis and
    proteinase K digestion. The lysate was diluted
    1:100 and its absorbance measured in an
    ultraviolet spectrophotometer at 260 nm and
    280 nm. The absorbance ratio 260:280 was
    1.2. What does this indicate?
    A. The DNA concentration is too high for PCR
    B. The DNA concentration is too low for PCR
    C. The sample contains too much protein
    D. The sample is optimal for PCR

Answer 36

C. The sample contains too much protein

Question 37

37. Which method of analysis is considered the most
    reliable means of detecting mutations of BRCA,
    p53, BRAF, and other genes linked to cancer?
    A. FISH
    B. Immunohistochemistry
    C. Sequencing
    D. STR analysis

Answer 37

C. Sequencing

Question 38

38. An assay based on the principle of proteomics may
    be used for which of the following?
    A. Screening for colorectal cancer
    B. Screening for lung cancer
    C. Identifying malignant ovarian masses
    D. Identifying malignant breast tumors

Answer 38

C. Identifying malignant ovarian masses

Question 39

39. What method is used to identify maternal cell
    contamination in amniocentesis and chorionic
    villus samples (CVS)?
    A. STR analysis
    B. FISH
    C. Microarray analysis
    D. MicroRNA (MiRNA) analysis

Answer 39

A. STR analysis

Question 40

40. What is the clinical significance of K-ras testing?
    A. K-Ras mutations make tumor cells more
    susceptible to chemotherapy
    B. K-Ras is a tumor suppressor gene and mutations
    are associated with increased lifetime risk of
    malignancy
    C. K-Ras mutations result in treatment resistance to
    growth factor receptor inhibitors
    D. K-Ras is used to identify the tissue of origin

Answer 40

C. K-Ras mutations result in treatment resistance to
growth factor receptor inhibitors