Gene expression array testing of FFPE archival breast tumor samples: an optimized protocol for WG-DASL sample...

Area of Science:

• Molecular Biology
• Oncology
• Biotechnology

Background:

• Archived formalin-fixed, paraffin-embedded (FFPE) tissues are a valuable resource for cancer research.
• RNA extracted from FFPE tissues is often degraded and chemically modified, limiting its use in molecular studies.
• Existing RNA extraction methods are suboptimal for FFPE samples.

Purpose of the Study:

• To develop and validate a modified RNA extraction protocol for FFPE tissues.
• To assess the feasibility of gene expression profiling using RNA from FFPE samples.
• To evaluate the quality and utility of extracted RNA for molecular subtyping of breast cancer.

Main Methods:

• A modified RNA extraction protocol was applied to FFPE breast cancer tissues.
• Gene expression profiling was performed using the WG-DASL platform.
• Hierarchical clustering was used to analyze gene expression data and classify samples.

Main Results:

• The modified protocol achieved a 100% success rate for RNA extraction from FFPE samples.
• Gene expression data from FFPE samples showed high quality, with 100% replicate identification and high self-correlation (r=0.979).
• Samples were accurately classified into Estrogen Receptor-positive (ER+) and ER- subtypes with high specificity (95% and 90%, respectively).

Conclusions:

• The developed protocol enables successful gene expression profiling from decade-old FFPE breast cancer samples.
• This method overcomes limitations associated with RNA degradation in FFPE tissues.
• Archived FFPE samples can be reliably used for molecular studies, including cancer subtyping.