ABPath Molecular Genetic Pathology 2

Question 1

A patient's tumor shows microsatellite instability (MSI-high). Which pathway defect is most directly responsible?

Accepted Answer

DNA mismatch repair deficiency

Answer

Nucleotide excision repair defect

Answer

Homologous recombination deficiency

Answer

Base excision repair defect

Question 2

Which method distinguishes germline BRCA1 mutations from somatic mutations in a tumor sample?

Accepted Answer

Testing matched normal tissue such as blood

Answer

Increasing PCR cycle number

Answer

Using a longer amplicon

Answer

Adding more Taq polymerase

Question 3

The BCR-ABL1 fusion in chronic myeloid leukemia is best monitored for minimal residual disease using which assay?

Accepted Answer

Quantitative real-time RT-PCR

Answer

Sanger sequencing

Answer

Immunohistochemistry

Answer

Karyotype alone

Question 4

A Sanger sequencing electropherogram shows a double peak at a single position in a heterozygous sample. This most likely represents:

Accepted Answer

A heterozygous single-nucleotide variant

Answer

A homozygous deletion

Answer

A sequencing artifact requiring rejection

Answer

A large chromosomal translocation

Question 5

Which alteration is the primary target of EGFR tyrosine kinase inhibitor therapy in non-small cell lung cancer?

Accepted Answer

EGFR exon 19 deletion

Answer

KRAS G12C alone

Answer

TP53 missense mutation

Answer

MYC amplification

Question 6

In a Fragile X (FMR1) analysis, which molecular feature defines a full mutation?

Accepted Answer

More than 200 CGG repeats with hypermethylation

Answer

A point mutation in exon 1

Answer

Deletion of the entire gene

Answer

A balanced translocation at Xq27

Question 7

Digital droplet PCR offers an advantage over qPCR primarily because it provides:

Accepted Answer

Absolute quantification without a standard curve

Answer

Longer read lengths

Answer

Direct protein detection

Answer

Whole-genome coverage