Vibrational Spectroscopy and Cancer - Vibrational Spectroscopy for Tissue Analysis - page 59

Different layers of human cervical squamous tissue, representing different
cellular maturation stages, exhibited quite dissimilar spectral patterns.
Thus, it was concluded that this technique presents a powerful tool to
monitor cell maturation and differentiation. In addition, a proper interpre-
tation of the state of health of cells exfoliated from such tissues would be
obtained through a detailed understanding of the spectra of the individual
layers [50].
B. R. Wood et al. performed an FTIR microspectroscopic investigation of cell
types and potential confounding variables in screening for cervical malig-
nancies. The aim of the study was to determine the effectiveness of infrared
spectroscopy in the diagnosis of cervical cancer and dysplasia. It was found
that leukocytes, and in particular lymphocytes, have spectral features in the
phosphodiester region (1300-900 cm −1 ), suggestive of changes indicative of
malignancy. The use of ethanol as a fixative and dehydrating agent resulted
in retention of glycogen and thus minimized the spectral changes in the
glycogen region due to sampling technique. Erythrocyte spectra exhibited a
reduction in glycogen band intensity, but could be discerned by a relatively
low-intensity ν s PO 2 − band. Endocervical mucin spectra exhibit a reduction
glycogen band and a very pronounced ν s PO 2 − band, which was similar in
intensity to the corresponding band in HeLa ν s PO 2 − cells [51].
Utzinger et al. introduced a near-infrared Raman spectroscopic method
for in vivo detection of cervical precancers. The main focus of the project was
on squamous dysplasia, a precursor of cervical cancer. A pilot clinical trial
was carried out at three clinical sites. Raman spectra were measured from
one normal and one abnormal area of the cervix. These sites were then biop-
sied and submitted for routine histologic analysis. Twenty-four measures
were made in vivo in 13 patients. Cervical tissue Raman spectra contained
peaks in the vicinity of 1070, 1180, 1195, 1210, 1245, 1330, 1400, 1454, 1505, 1555,
1656, and 1760 cm −1 . The ratio of intensities at 1454 to 1656 cm −1 was greater
for squamous dysplasia than all other tissue types, while the ratio of inten-
sities at 1330 to 1454 cm −1 was lower for samples with squamous dysplasia
than all other tissue types. A simple algorithm based on these two intensity
ratios separated high-grade squamous dysplasia from all others, misclassi-
fying only one sample. Spectra measured in vivo resembled those measured
in vitro. It was believed that cervical epithelial cells may contribute to tissue
spectra at 1330 cm −1 , a region associated with DNA. In contrast, epithelial
cells probably do not contribute to spectra at 1454 cm −1 , a region associated
with collagen and phospholipids [52].
R. Sindhuphak et al. screened cervical cell samples of Thai women by
using FTIR spectroscopy, and compared the results to the histologic diagno-
sis. A total of 275 cervical cell specimens were received from patients under-
going hysterectomy. Histological examinations showed 108 normal cases
and 167 abnormal cases. FTIR results versus histology showed sensitivity of
96.3% and specificity of 96.4%. False negative and false positive rates were
3.7 and 3.6%, respectively [53].