Molecular Pathology - Lung Flashcards
Recall the most common, usually mutually exclusive mutations found in lung adenocarcinoma, and their frequency.
Who do they usually affect?
K-RAS (25%) - Smokers
EGFR (15%, usually L858R) - Asians
ALK / RET / ROS (10%) - Younger patients
Minor: RET, BRAF, ERBB2, MET
What mutations are often found in squamous cell carcinoma of lung?
Smoking related mutations, usually p53. No driving mutations.
FGFR3 and PI3K/PTEN/AKT mutations are less common.
With respect to lung adenocarcinoma:
How common are p53 mutations?
What is the significance of STK11 mutations?
What is the significance of PI3K/PTEN/AKT mutations?
p53 mutations are found in 50% of lung adenocarcinomas
STK11 mutations are found in association with K-RAS and confer resistance to MEK inhibitors.
PI3K/PTEN/AKT confer resistance to EGFR inhibitors.
What mutations are usually found in small cell lung carcinoma?
TP53, RB1.
MYC-amplification less often.
What morphologies are associated with EGFR mutation in lung adenocarcinoma?
Bonus: Recall their significance.
Acinar - More likely to recur in presence of cribriforming
Lepidic - Usually adenocarcinomas in situ
Micropapillary - Increased lymph node metastasis
Papillary
What morphologies are seen in lung adenocarcinoma with:
K-RAS mutation?
ALK/ROS/RET?
K-RAS: Solid-predominant
ALK/ROS/RET - Extracellular mucin and prominent signet ring cells
Describe the mutations found in lung adenocarcinoma in situ.
Follows lung adenocarcinoma, with particular association with EGFR mutations.
What mutations are found in invasive mucinous adenocarcinomas?
Usually K-RAS mutations.
What is the significance of MET mutations?
Found in at least lung adenocarcinomas, they confer aggressive behavior, but can be targeted by MET inhibitors like crizotinib.
What mutations are found in large cell carcinomas?
TP53, K-RAS
What mutations are found in adenosquamous carcinomas?
Same as adenocarcinomas; EGFR, K-RAS, ALK-RET-ROS
What mutations are found in pleomorphic/sarcomatoid carcinomas?
MET and K-RAS.
EGFR in asian populations.
What is NUT carcinoma?
How it is characterized?
A rare and aggressive carcinoma that affects the head & neck, lung, and salivary glands.
Sheets of undifferentiated cells with NUT overexpression and NUTM1 gene fusion.
What salivary gland tumors are found in lung, and what mutations drive them?
Mucoepidermoid carcinoma - MAML2 rearrangement
Adenoid cystic carcinoma - MYB rearrangement
Hyalinizing clear cell carcinoma - EWSR1 rearrangement
What are the preferred methods of detection for:
EGFR?
K-RAS
ALK?
EGFR - Sequencing
K-RAS - Sequencing
ALK - FISH
