The chemical carcinogens from tobacco are related to over 90% of lung cancers around the world. The
risk of death of this kind of cancer is high because the diagnosis usually is made only in advanced stages.
Therefore, it is necessary to develop new diagnostic methods for detecting the lung cancer in earlier
stages. The Fourier Transform Infrared Spectroscopy (FTIR) can offer high sensibility and accuracy to
detect the minimal chemical changes into the biological sample. The aim of this study is to evaluate the
differences on infrared spectra between normal lung cells and precancerous lung cells transformed by
NNK. Non-cancerous lung cell line e10 (ATCC) and NNK-transformed e10 cell lines were maintained in
complete culture medium (1:1 mixture of Dulbecco's modified Eagle's medium and Ham's F12
[DMEM/Ham's F12], supplemented with 100 ng/ml cholera enterotoxin, 10 lg/ml insulin, 0.5 lg/ml.
hydrocortisol, 20 ng/ml epidermal growth factor, and 5% horse serum. The cultures were maintained in
alcohol 70%. The infrared spectra were acquired on ATR-FTIR Nicolet 6700 spectrophotometer at 4 cm<sup>-1</sup>
resolution, 30 scans, in the 1800-900 cm<sup>-1</sup> spectral range. Each sample had 3 spectra recorded, 30
infrared spectra were obtained from each cell line. The second derivate of spectra indicates that there are
displacement in 1646 cm<sup>-1</sup> (amine I) and 1255 cm<sup>-1</sup>(DNA), allowing the possibility to differentiate the
two king of cells, with accuracy of 89,9%. These preliminary results indicate that ATR-FTIR is useful to
differentiate normal e10 lung cells from precancerous e10 transformed by NNK.