Vibrational Spectroscopy and Cancer - Vibrational Spectroscopy for Tissue Analysis - page 60

A study was conducted by Mordechai et al. on formalin fixed melanoma
and cervical cancer by FTIR microspectroscopy (FTIR-MSP), to detect com-
mon biomarkers that occur in both types of cancer, distinguishing them
from the respective nonmalignant tissues. The spectra were analysed for
changes in levels of biomolecules such as RNA, DNA, phosphates, and car-
bohydrates. Whereas carbohydrate levels showed a good diagnostic poten-
tial for detection of cervical cancer, this was not the case for melanoma.
However, variation of the RNA/DNA ratio as measured at 1121/1020 cm −1
showed similar trends between nonmalignant and malignant tissues in both
types of cancer. The ratio was higher for malignant tissues in both types of
cancer [54].
L. Chiriboga et al. carried out a comparative study of spectra of biopsies
of cervical squamous epithelium and of exfoliated cervical cells using infra-
red spectroscopy. A comparison of infrared absorption spectra obtained
from the different layers of squamous epithelium from the human cervix,
and infrared spectra obtained from exfoliated cervical cells was done. It was
shown that the technique is a sensitive tool to monitor maturation and dif-
ferentiation of human cervical cells. Therefore, it was concluded that this
spectroscopic method provides new insights into the composition and state
of health of exfoliated cells [55].
Wong carried out research on exfoliated cells and tissues from human
endocervix and ectocervix by FTIR and attenuated total reflectance (ATR)/
FTIR spectroscopy. They measured the transmission infrared spectra of
exfoliated endocervical mucin-producing columnar epithelial cells and the
ATR infrared spectra of the single-columnar cell layer on the endocervical
tissues and compared with the corresponding infrared spectra of ectocervi-
cal squamous cells and squamous epithelium. The effects of the contami-
nated connective tissue on the infrared spectra of the endocervical columnar
epithelial tissue demonstrated that ATR/FTIR is a more desirable method
than the transmission method to obtain meaningful and good-quality infra-
red spectra of tissue samples, especially samples consisting of thin layers
of different types of tissues. Substantial differences in the infrared spectra
between the columnar cells and squamous cells on the endocervical and
ectocervical tissues, respectively, were evident. The strong glycogen bands
in the infrared spectrum of the ectocervical squamous cells were absent in
the spectrum of endocervical columnar cells. These spectral changes were
similar to that observed in malignant squamous cells. Therefore, if the
decrease in the intensity of the glycogen bands is used as the only criterion
for the determination of the cellular abnormalities in the cervix, the pres-
ence of a large number of normal endocervical columnar cells in the cervi-
cal specimen would lead to a false result. Consequently, it was concluded
that in addition to the glycogen bands, other features in the infrared spectra
should be considered for evaluation of abnormalities in exfoliated cervical
epithelial cells [56].