A study of hormonal effects in cervical smear samples using Raman spectroscopy

Abstract

Raman spectroscopy is a powerful tool that has the potential to be used as a screening method for cervical cancer. It is a label-free, low-cost method providing a biochemical fingerprint of a given sample. The objective of this study was to address patient-to-patient variability contributed by hormonal effects due to the menstrual cycle, the use of hormone-based contraceptives (HC) and the onset of menopause, and to determine if these changes would affect the ability to successfully identify dyskaryotic cells. Raman spectra were recorded from unstained ThinPrep cervical samples (45 cytology negative and 15 high-grade dyskaryosis (high-grade squamous intraepithelial lesion, HSIL) samples using a HORIBA Jobin Yvon XploRA system. HPV DNA testing was also performed. Clinical data collected included date of the last menstrual period, the use of HC and/or menopausal status. Spectral changes were observed depending on the day of the menstrual cycle and on the use of HC. Despite this, HSIL could be discriminated from normal cells regardless of the day on which the sample was taken or the use of HC.

Raman spectral signatures of cervical exfoliated cells from liquid-based cytology samples

“…However, a recent study from our group showed some changes in glycogen related peaks in the spectra from the nuclei of intermediate cells but no significant difference in glycogen in the spectra from the nuclei of superficial cells across the menstrual cycle. 33 As spectra were recorded from the cell nuclei in the study by Traynor et al 33 rather than from the cytoplasm as in this study or from cell pellets as in the study by Romeo et al, 40 no significant variability due to glycogen was observed and Raman spectroscopy was shown to discriminate well between negative cytology samples taken across different days of the menstrual cycle and HSIL cytology samples.…”

“…Ramos et al 24 reported sensitivity and specificity values of >90% for classification of negative, CIN1, CIN2, and CIN3 cervical cytology samples. Recently, Traynor et al 33 investigated hormone-associated changes in the Raman spectra of cytologically negative ThinPrep cervical smear samples related to the menstrual cycle, the use of hormone-based contraceptives, and the onset of menopause, and showed that any spectral changes did not interfere with the ability to discriminate between normal and abnormal cervical cytology samples. This study follows on from this and focuses on defining the spectral signatures of different types of cervical exfoliated cells.…”

Raman Spectroscopy of Liquid-Based Cervical Smear Samples as a Triage to Stratify Women Who Are HPV-Positive on Screening

“…Data preprocessing was performed using Matlab software (Mathworks Inc., Natick, MA, USA) and in-house scripts, including smoothing (Savitzky-Golay K = 5, K = 13), baseline correction (rubberband), and vector normalization. A non-negative least-squares (NNLS) method was used for glass correction as described previously [ 27 , 29 ]. The data were mean-centered and partial least squares discriminant analysis (PLS-DA) using the PLS toolbox (Eigenvector Research, Washington, DC, USA) in the Matlab (Mathworks Inc., Natick, MA, USA) environment was used to build classification models.…”

“…As an alternative approach to single molecular biomarkers, Raman spectroscopy can provide a biochemical fingerprint of a cell or tissue [ 12 , 13 ] and, thus, offers an opportunity to capture molecular changes in one test. Many studies have shown the potential of Raman spectroscopy for noninvasive, objective detection of cervical cancer and precancer in cells and tissues [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ], but there are limited studies on detection of HPV infection.…”

“…Vargis et al [ 16 ] showed discrimination between different HPV-negative and HPV-positive cell lines and cytology samples using Raman spectroscopy. More recently, biochemical changes due to HPV infection in HSIL cells were shown to be more marked than biochemical changes due to the menstrual cycle or the use of hormonal contraceptives [ 29 ].…”