Pathology

Question 1

What IHC stains identifies Neuroendocrine differentiation?

Answer 1

CD56
Chromogranin
Synaptophysin

Question 2

What is TTF-1

Answer 2

A homeodomain-containing nuclear transcription protein of the Nkx2 gene family.

Expressed in epithelial cells of the embryonal & mature lung and thyroid

Question 3

What is Napsin A?

Answer 3

An Aspartic proteinase expressed in normal Type II pneumocystis and in proximal and distal renal tubules

Question 4

What are the immunostains relatively sensitive and specific for mesothelioma?

Answer 4

WT-1
Calretinin
D2-40
HMBE-1
Cytokeratin 5/6

Question 5

Which EGFR Exon 20 mutation is sensitive to EGFR TKIs?

Answer 5

EGFR Exon 20 S768I mutation

Question 6

What is acquired resistance to EGFR TKI therapy a/w?

Answer 6

1) Second-site mutations within the EGFR kinase domain (Eg. T790M)
2) Amplification of alternative kinases (eg. MET)
3) Histological transformation from NSCLC to SCLC
4) Epithelial to Mesenchymal transition (EMT)