KRAS testing on colo-rectal carcinoma cytological imprints

Area of Science:

• Oncology
• Molecular Diagnostics
• Gastroenterology

Background:

• Anti-EGFR monoclonal antibodies (cetuximab, panitumumab) are standard for advanced colorectal cancer (CRC) with wild-type KRAS.
• KRAS genotyping is crucial for patient selection, necessitating reliable and timely diagnostic methods.

Purpose of the Study:

• To evaluate the reliability of rapid KRAS mutation testing on ex vivo cytological samples from colorectal cancer (CRC) tissue.
• To assess the feasibility of using imprint cytology for KRAS genotyping concurrently with surgery.

Main Methods:

• 20 primary CRC specimens were analyzed.
• Imprint cytology slides were prepared from fresh tumor tissue, air-dried, and Diff-Quik stained.
• KRAS exon 2 mutations were assessed using dideoxy sequencing and the DxS KRAS Mutation Test Kit on both cytology and matched histology samples.

Main Results:

• Full concordance was observed between imprint cytology and matched histological samples.
• The DxS KRAS Mutation Test Kit detected a slightly higher mutation frequency (35%) compared to dideoxy sequencing (30%).
• Colon cancer imprint cytology proved to be a reliable biospecimen for KRAS mutation analysis.

Conclusions:

• Colon cancer imprint cytology is a reliable method for KRAS genotyping.
• This approach can potentially reduce the turnaround time for KRAS assay results.
• Rapid KRAS testing via imprint cytology supports timely therapeutic decisions in CRC management.