Discrimination of Melanoma Using Laser-Induced Breakdown Spectroscopy Conducted on Human Tissue Samples

Abstract

Discrimination and identification of melanoma (a kind of skin cancer) by using laser-induced breakdown spectroscopy (LIBS) combined with chemometrics methods are reported. The human melanoma and normal tissues are used in the form of formalin-fixed paraffin-embedded (FFPE) blocks as samples. The results demonstrated higher LIBS signal intensities of phosphorus (P), potassium (K), sodium (Na), magnesium (Mg), and calcium (Ca) in melanoma FFPE samples while lower signal intensities in normal FFPE tissue samples. Chemometric methods, artificial neural network (ANN), linear discriminant analysis (LDA), quadratic discriminant analysis (QDA), and partial least square discriminant analysis (PLS-DA) are used to build the classification models. Different preprocessing methods, standard normal variate (SNV), mean-centering, normalization by total area, and autoscaling, were compared. A good performance of the model (sensitivity, specificity, and accuracy) for melanoma and normal FFPE tissues has been achieved by the ANN and PLS-DA models (all were 100%). The results revealed that LIBS combined with chemometric methods for detection and discrimination of human malignancies is a reliable, accurate, and precise technique.

A Review on Laser-Induced Breakdown Spectroscopy in Different Cancers Diagnosis and Classification

“…To test and pick representative spectral lines, the MIE procedure was used, while column-wise Gaussian weighted lines based on the chosen feature lines and surrounding spectral lines, averaging was used to process two-dimensional spectral images. Khan et al [53] recently used LIBS combined with chemometric methods to examine and discriminate against human melanoma FFPE tissue samples instead of animal samples, and achieved good classification results as shown in Figure 6.…”

Discrimination of normal and cancerous human skin tissues based on laser-induced spectral shift fluorescence microscopy

“…As the tumor progresses, the nest shows mitotic activity. On the other hand, BCC demonstrates a relatively higher N/C ratio 28 , giving a deep blue appearance. The basaloid nest shows a preferable palisade alongside the apparent clefts.…”

“…In addition, benign nevi benefit no obliteration of active fluorophores leading to the longest emission wavelength as dark red. Furthermore, cancerous tumors deform and terminate the collagen fibers 28 , so the cancerous lesions suffer collagen destruction creating active sites for Rd6G attachments regarding normal tissues. As a result, a practical way is proposed to identify the degree of nonmelanoma neoplasia.…”

“…Polarimetry discriminates benign tissues from cancerous skin lesions based on Mueller matrix elements, including diattenuation, depolarization, and retardance parameters. For instance, regarding the nucleus to cytoplasm ratio (N/C), the malignant lesions benefit from a smaller depolarization against the benign nevus 27 , 28 .…”

Atomic spectrometry update: review of advances in the analysis of clinical and biological materials, foods and beverages

“…Using PCA first to rationalise the data, k -nearest neighbour, SVM and ANN classifiers were applied, with all three achieving accuracies of >90%. Melanoma was the focus of a research by Khan et al 93 who utilised LIBS with formalin fixed paraffin embedded tissues from normal samples ( n = 110) and stage III C patients ( n = 110). It was noted that enhanced signals for Ca, K, Mg, Na and P were observed in the melanoma samples.…”