Towards automated cancer screening: Label‐free classification of fixed cell samples using wavelength modulated Raman spectroscopy

• Published in: Journal of biophotonics 2018-04, Vol.11 (4), p.e201700244-n/a
• Main Authors: Woolford, Lana, Chen, Mingzhou, Dholakia, Kishan, Herrington, C. Simon
• Format: Article
• Language: English
• Subjects: Automation; Cancer; Cancer screening; Cell Line, Tumor; Cervix; Classification; Early Detection of Cancer; Epithelial cells; Epithelial Cells - pathology; Fluorescence; Full; Genetic transformation; Human papillomavirus; Humans; Intracellular Space - metabolism; Mass Screening - methods; Medical screening; Raman spectroscopy; screening; Sensitivity; Smear; Spectroscopy; Spectrum analysis; Spectrum Analysis, Raman; Wavelength
• ISSN: 1864-063X; 1864-0648; 1864-0648
• DOI: 10.1002/jbio.201700244

The ability to provide quantitative, objective and automated pathological analysis would provide enormous benefits for national cancer screening programmes, in terms of both resource reduction and improved patient wellbeing. The move towards molecular pathology through spectroscopic methods shows great promise, but has been restricted by spectral quality, acquisition times and lack of direct clinical application. In this paper, we present the application of wavelength modulated Raman spectroscopy for the automated label‐ and fluorescence‐free classification of fixed squamous epithelial cells in suspension, such as those produced during a cervical smear test. Direct comparison with standard Raman spectroscopy shows marked improvement of sensitivity and specificity when considering both human papillomavirus (sensitivity +12.0%, specificity +5.3%) and transformation status (sensitivity +10.3%, specificity +11.1%). Studies on the impact of intracellular sampling location and storage effects suggest that wavelength modulated Raman spectroscopy is sufficiently robust to be used in fixed cell classification, but requires further investigations of potential sources of molecular variation in order to improve current clinical tools. Molecular pathology shows significant promise for improving the cost, time and subjectivity of current cervical screening practice. This paper explores the use of Raman spectroscopy for the automatic categorisation of fixed cells through analysis of their intrinsic molecular vibrations. The addition of wavelength modulation to the laser provides autofluorescence rejection and a marked improvement in both the sensitivity and specificity of cell line classification.