Detecting and Monitoring of Cancer at the Cellular Level - Vibrational Spectroscopy for Tissue Analysis - page 164

In general, testicular cancer is not very common: only 1 to 2 of every 100
cancers diagnosed in men are testicular cancers [8]. It is most common among
males aged 15-40 years [9] and is the most common cancer affecting young
men between 20 and 39 years [8]. Only about 1 in 7 (14%) are diagnosed in
men over 50 years [8]. Over the lifetime of a male, the risk of developing tes-
ticular cancer is roughly 1 in 250 (four tenths of one percent, or 0.4%) [9,10].
Around 2,100 men are diagnosed in the United Kingdom and 7,500 to 8,000
diagnoses of testicular cancer are made in the United States each year [8,9].
Testicular cancer has one of the highest cure rates of all cancers [8,9] and
chemotherapy offers a cure rate of at least 85% today [10,11]. Similar to other
malignancies, this type of cancer can be sensitive or resistant to chemothera-
peutic medications. It would be greatly beneficial if clinicians could deduce
if cancer strains are sensitive or resistant to chemotherapy prior to a main
course of chemotherapy treatment as this could help determine the best
approach to use.
Spectral acquisition
In this study, the Raman spectroscopic technique was employed to analyse
testicular cancer cell line samples. A total of 12 samples, which included six
resistant and six sensitive (to chemotherapeutic medications) subtypes, were
analysed.
Raman spectra of the samples were recorded using an Almega (Thermo
Fisher Scientific, Madison Wisconsin, USA), equipped with two types of
lasers. The first laser was a 532-nm (green) diode-pumped solid-state laser,
with a laser power of 25 mW TEM00 continuous wave beam, and power sta-
bility of < 5%. The second laser, which was also the main one employed in
this work, was a 785-nm near-infrared (NIR) high-power diode laser, with a
laser power of 300 mW, multimode continuous wave beam, and power stabil-
ity of < 5%. It must be mentioned that the laser power can be changed from
15 to 100%, according to the requirements of experiments. The machine also
has an Andor DV420 open electrode CCD detector, with a working tempera-
ture of −50°C. All of the spectra were collected in the range 96-3430 cm −1
using 10X objectives and more than an average of 64 scans.
The samples used in this research are ATTC cancer cell lines. After defrost-
ing, the cell lines are cultured in culturing media and incubated. Culture
medium is then removed, and an adequate quantity of 10% trypsin is added
to detach the cells. The cells (in trypsin) are transferred into a 50-mL centri-
fuge tube containing an equal volume of fresh culture medium to neutralise
the trypsin. After centrifuging, the supernatant is tipped off and the pellet
resuspended in fresh culture medium. In this stage, the cells are counted
by trypan blue method and 3 × 10 6 cells are calculated and transferred into
a 15-mL centrifuge tube. After centrifuging another time, the pellet is resus-
pended in 5 mL of 70% ethanol and frozen until ready to analyse. Samples
were prepared for spectroscopic investigation by removing the ethanol