Cytopathology by optical methods: spectral cytopathology of the oral mucosa

Abstract

Spectral cytopathology (SCP) is a novel approach for diagnostic differentiation of disease in individual exfoliated cells. SCP is carried out by collecting information on each cell's biochemical composition through an infrared micro-spectral measurement, followed by multivariate data analysis. Deviations from a cell's natural composition produce specific spectral patterns that are exclusive to the cause of the deviation or disease. These unique spectral patterns are reproducible and can be identified and used through multivariate statistical methods to detect cells compromised at the molecular level by dysplasia, neoplasia, or viral infection. In this proof of concept study, a benchmark for the sensitivity of SCP is established by classifying healthy oral squamous cells according to their anatomical origin in the oral cavity. Classification is achieved by spectrally detecting cells with unique protein expressions: for example, the squamous cells of the tongue are the only cell type in the oral cavity that have significant amounts of intracytoplasmic keratin, which allows them to be spectrally differentiated from other oral mucosa cells. Furthermore, thousands of cells from a number of clinical specimens were examined, among them were squamous cell carcinoma, malignancy-associated changes including reactive atypia, and infection by the herpes simplex virus. Owing to its sensitivity to molecular changes, SCP often can detect the onset of disease earlier than is currently possible by cytopathology visualization. As SCP is based on automated instrumentation and unsupervised software, it constitutes a diagnostic workup of medical samples devoid of bias and inconsistency. Therefore, SCP shows potential as a complementary tool in medical cytopathology. KEYWORDS: cytopathology; infrared micro-spectroscopy; malignancy-associated changes; multivariate statistics; squamous cell carcinoma; spectral cytopathology A significant amount of attention and awareness has converged on oral cancer in recent years, a response by the medical community to the fact that it has become the sixth most common cancer worldwide. Of those newly diagnosed with oral cancer, only half will survive within 5 years, a characteristic attributed to oral cancer's high recurrence rates and metastasis relative to most other cancers. In fact, it is well established that for oral cancers, patients who survive their first encounter with the disease have up to a 20 times higher risk of developing a second cancer, a characteristic attributed to 'field cancerization' or malignancy-associated changes (MACs), which represent a biochemical change shown to be diagnostic in this paper. Furthermore, fatalities by oral cancers have not decreased in decades; earlier diagnosis and treatment modalities are needed. The medical community recognizes that without the implementation of new standardized screening procedures, oral cancers are found too late at metastatic stages in which the cancer has progressed to involve lymph nodes of the neck. Prognosis and treatment option...

Molecular pathology via IR and Raman spectral imaging

“…Preliminary results on oral SCP from a smaller cohort of patients and volunteers were previously reported [76,75,84]. This study demonstrated small differences in spectral features observed for different anatomical regions of the oral cavity, and a clear differentiation between normal and cancer cells.…”

“…These developments have led to several studies which detailed application of the methodology to both cervical and oral squamous cells [23,[82][83][84]. Based on the success of these studies, an expanded pre-clinical trial was carried out at the LSpD, the results of which will be presented in this section.…”

Infrared spectral histopathology (SHP): a novel diagnostic tool for the accurate classification of lung cancer

“…We believe that this technology can aid in the accurate diagnosis of cancers that are difficult to distinguish on a morphological basis alone, and whose accurate diagnoses determine therapeutic options. This report follows similar studies from the same laboratory in which equivalent methods for the analysis of exfoliated cells were reported, [29][30][31] using a methodology referred to as spectral cytopathology (SCP). SCP proved to be more sensitive than classical cytopathology in that morphologically normal cells from abnormal (dysplastic) samples exhibited spectral changes that could be associated with a transition from normal to pre-cancerous states.…”

The Role and Application of Exfoliative Cytology in the Diagnosis of Oral Mucosa Pathology – Contemporary Knowledge with Review of the Literature

“…According to their studies, the advantages of SCP are the possibility of monitoring the biochemical arrangement of particular cells, and analyzing the spectral information. This mathematical process provides an impartial, recurrent approach to help cytopathologists and to increase the standard of care for the patient [15].…”