An investigation into FTIR spectroscopy as a biodiagnostic tool for cervical cancer

Abstract

Fourier-transform infrared (FTIR) microspectroscopy, combined with Principal Component Analysis (PCA), was applied in the study of exfoliated cervical cells from 272 patients. Six spectra were recorded for each patient, and these were visually sorted into two types (type 1 and type 2), based on their profiles. Spectra designated type 1 exhibited a profile characteristic of normal epithelial cells, with intense glycogen bands at 1022 cm−1 and 1150 cm−1, and a pronounced symmetric phosphate stretch at 1078 cm−1. Spectra designated type 2 exhibited features suggestive of dysplastic or malignant transformation, with pronounced symmetric and asymmetric phosphate modes and a reduction in glycogen-band intensity. Of the 272 patients, 68.6% of samples exhibited only type 1 profiles for all six recorded spectra, 29.4% of samples yielded at least one type 2 spectrum in any of the six recorded spectra and 2% of samples were inconclusive. Of the 68.6%, 86% were diagnosed normal by Pap smear with no follow up biopsy ordered, 7% were diagnosed abnormal by biopsy, 5% normal by biopsy and 2% were still inconclusive. For the remaining 29.4% of classified samples, 71% had shown an abnormal Pap result. These 71% were subsequently biopsied, and 87% were confirmed abnormal. The association of type 2 spectra and abnormality was further corroborated by spectra of cultured malignant cells from the HeLa cell line that displayed a profile similar to type 2 spectra in the 1300-950 cm−1 region. PCA decomposition using a reduced data matrix resulted in a score plot that showed general separation of the visually categorised spectra. This study demonstrates the potential of automated FTIR cervical screening technology in the clinical environment. © 1996 John Wiley & Sons, Inc.