Protein Conformational Changes in Breast Cancer Sera Using Infrared Spectroscopic Analysis

Area of Science:

• Biophysics
• Biochemistry
• Medical Diagnostics

Background:

• Protein misfolding and aggregation are linked to various diseases, including cancer.
• Clinical applications of infrared spectroscopy for detecting cancer-associated protein structural changes remain underexplored.

Purpose of the Study:

• To investigate the potential of Fourier transform infrared spectroscopy (FTIR) in differentiating breast cancer patient sera from healthy individuals.
• To analyze cancer-associated alterations in protein structure and circulating nucleic acids using FTIR.

Main Methods:

• Analysis of the amide I band (1600-1700 cm⁻¹) of FTIR spectra to assess protein structural changes (α-helix and β-pleated sheet ratios).
• Comparison of absorbance ratios at amide II and amide III bands (I₁₅₅₆/I₁₂₉₅) as infrared spectral signatures.
• Extension of spectral fitting to the 1140-1000 cm⁻¹ region to evaluate alterations in carbohydrates and nucleic acids.

Main Results:

• The ratio of α-helix to β-pleated sheet showed 90% sensitivity and 90% specificity.
• The ratio of amide II to amide III absorbance (I₁₅₅₆/I₁₂₉₅) demonstrated 100% sensitivity and 80% specificity.
• FTIR successfully distinguished between healthy and breast cancer serum samples based on spectral signatures.

Conclusions:

• Infrared spectroscopy is a powerful tool for analyzing protein structural alterations in serum.
• FTIR can effectively distinguish breast cancer serum samples from healthy controls, indicating its potential as a diagnostic biomarker.