Infrared and Raman Spectroscopy and Imaging of Breast Cancer - Vibrational Spectroscopy for Tissue Analysis - page 127

0.6

A

0.5

0.4

0.3

0.2

0.1

0.0

1800 1600

Wavenumber, cm -1 1200

1400 1000 800

0.7

B

164 1630

0.6

1542

0.5

1522

0.4

0.3

0.2

0.1

0.0

1700 1600 1500 1400

Wavenumber, cm -1

Figure 5.15 (See colour insert.)
A: FTIR spectra of sections from DCIS, (LNG in black, ING in blue, and HNG in red). B: Variation
in intensity of the peaks in the spectral region 1700-1400 cm −1 .

This is due to the fact that the infrared absorption band for amide I groups
is sensitive to protein conformation; therefore, this band can be employed to
grade the DCIS tissue, in addition to relative intensities.
In the amide I and II area, a pattern similar to IDC samples was observed in
DCIS samples (Figures 5.15B and 5.13B). In both cases, whilst amide I upshifts
toward 1640 cm −1 , amide II downshifts to 1522 cm −1 , indicating secondary
structure alterations.
The presence of peaks centred at 1310-1300 cm −1 (amide III band of pro-
teins) [46], in the 1700-900 cm −1 region can be attributed to type I collagen
(Figure 5.15 and 5.16C). The difference in intensity and shape of these peaks
indicates the varying type and amount of type I collagen present in the
three nuclear-grade tissues (Figure 5.16C). Therefore, combining the three