Digitally guided microdissection aids somatic mutation detection in difficult to dissect tumors

Area of Science:

• Oncology
• Molecular Pathology
• Biotechnology

Background:

• Molecular genetic testing of tumors often requires tissue dissection from slides.
• Manual macrodissection is a common technique but can be insufficient for low tumor content samples.
• Formalin-fixed, paraffin-embedded (FFPE) tissues are frequently used for molecular testing.

Purpose of the Study:

• To compare the effectiveness of manual macrodissection and digitally guided microdissection for FFPE tumor samples.
• To assess the impact of dissection method on KRAS hotspot mutation detection in pancreatic cancer.
• To evaluate tumor cellularity and DNA yield between the two dissection techniques.

Main Methods:

• 32 FFPE pancreatic cancer samples were analyzed.
• Manual macrodissection was performed based on pathologist-marked H&E slides.
• Digitally guided microdissection was performed on selected high-tumor-content areas.
• KRAS hotspot mutation profiling was conducted using Sequenom MassARRAY.

Main Results:

• Digitally guided microdissection yielded significantly higher KRAS mutant allele fraction and neoplastic cellularity (p < 0.01).
• 7 out of 32 samples (22%) showed detectable mutations exclusively with digitally guided microdissection.
• DNA quality and yield per volume were comparable between both methods.

Conclusions:

• Digitally guided microdissection offers a significant improvement in achievable tumor content from FFPE tissues.
• This advanced technique enhances the sensitivity of molecular testing, particularly for samples with limited tumor cellularity.
• Digitally guided microdissection is a valuable tool for molecular genetic testing of FFPE tumor samples.