Collagen I fiber density increases in lymph node positive breast cancers: pilot study

Area of Science:

• Oncology
• Biophysics
• Biomaterials

Background:

• Collagen I (Col1) fibers are key structural elements in the extracellular matrix of human breast cancers.
• The relationship between Col1 fiber density and lymph node metastasis in breast cancer requires further investigation.

Purpose of the Study:

• To explore the association between Collagen I fiber density in primary breast tumors and the presence of lymph node metastasis.
• To evaluate Collagen I fiber density as a potential imaging biomarker for breast cancer metastasis.

Main Methods:

• Utilized second harmonic generation (SHG) microscopy to detect and quantify Col1 fibers in primary breast tumors.
• Employed in-house SHG image analysis software for quantitative assessment of Col1 fiber density (fiber volume, inter-fiber distance).
• Performed texture analysis using co-occurrence matrix and Fourier transform to characterize Col1 fiber organization.

Main Results:

• Significantly higher Col1 fiber volume was observed in primary breast cancers of lymph node-positive (LN+) patients (29.22%±4.72%) compared to lymph node-negative (LN-) patients (20.33%±5.56%).
• Inter-fiber distance was smaller in LN+ patients (2.25±0.45 µm) versus LN- patients (2.88±1.07 µm).
• Texture analysis revealed significant differences in correlation, energy, aspect ratio, and eccentricity between LN+ and LN- cases, indicating distinct fiber organization patterns.

Conclusions:

• Increased Collagen I fiber density in primary breast tumors is associated with lymph node metastasis in breast cancer.
• Col1 fiber density, as assessed by SHG microscopy, shows potential as a non-invasive imaging biomarker for predicting breast cancer metastasis.
• Standard tissue fixation and paraffin embedding methods do not significantly impact SHG-based Col1 fiber detection and quantification.