Long non-coding RNA chromogenic in situ hybridisation signal pattern correlation with breast tumour pathology

Area of Science:

• Molecular biology
• Oncology
• Biomarker discovery

Background:

• Long non-coding RNAs (lncRNAs) are emerging as critical players in cancer biology.
• Traditional methods for lncRNA detection include RNA sequencing and PCR, which may not provide spatial information.
• Chromogenic in situ hybridisation (CISH) offers a potential alternative for visualizing lncRNA expression within tissue architecture.

Purpose of the Study:

• To investigate the expression patterns of six breast cancer-associated lncRNAs using CISH.
• To determine if CISH can differentiate between normal and cancerous breast tissues based on lncRNA expression.
• To assess the utility of CISH as a clinical assay for breast cancer risk stratification.

Main Methods:

• Tissue samples from 52 patients, including invasive breast carcinoma (IBC), ductal carcinoma in situ (DCIS), and normal adjacent (NA) tissues, were analyzed.
• Chromogenic in situ hybridisation (CISH) was employed to detect the expression of six specific lncRNAs.
• Staining intensity was quantified using the modified Allred scoring system.

Main Results:

• Three lncRNAs (HOTAIR, H19, KCNQ1OT1) showed significantly higher expression in both IBC and DCIS compared to NA tissues (p<0.05).
• HOTAIR and H19 exhibited stronger expression in IBC than in DCIS tissues (p<0.05).
• Specific lncRNAs were localized to different cellular compartments: HOTAIR and KCNQ1OT1 in tumor cells, H19 and MEG3 in stromal cells, MALAT1 in all cells, and ZFAS1 showed weak/negative expression.

Conclusions:

• The findings confirm the involvement of HOTAIR, H19, and KCNQ1OT1 in breast tumorigenesis.
• CISH is validated as a promising technique for detecting lncRNA expression in breast cancer.
• CISH provides crucial information on the specific tissue compartments where lncRNAs are expressed, aiding in understanding their functional roles.