| Abstract: | Confocal Raman microspectroscopy (CRM) continues to develop as a promising technique with possible clinical applications for the diagnosis and treatment of skin cancers. CRM studies of single cells can provide information on the biochemical content of cancer cells in situ, potentially providing new biochemical signatures or markers of cancer cells. Here, we report a CRM study of single, living human metastatic melanoma cells (SK‐Mel‐2) and normal skin fibroblast cells (BJ) cultured and examined under identical experimental conditions. A total of almost 1200 Raman spectra were measured from more than 120 BJ and SK‐Mel‐2 cells using an inverted microscope with 647 nm laser excitation. Raman spectra were measured from within three distinct intracellular regions of the cells – cytoplasm, nucleoplasm, and nucleolus. When Raman spectra from each cell type were compared using principal components analysis (PCA) and linear discriminant analysis with leave‐one‐dish‐out cross‐validation (LDA‐CV), the two cell types were discriminated with 93% (cytoplasm), 98% (nucleolus), and 96% (nucleoplasm) accuracy. The main biochemical differences identified between the two cell types were higher RNA levels in the nucleoli of BJ cells and high amounts of lipid and collagen in the cytoplasm of SK‐Mel‐2 cells. For both cell types, higher levels of RNA were detected in the nucleoli versus the nucleoplasm. PCA with LDA‐CV was 98% (cytoplasm), 93% (nucleoplasm), and 73% (nucleolus) accurate in identifying the intracellular region based on the Raman spectra from both cell types. No significant trend was observed when the data were analyzed with respect to cell passage number. Thus, CRM with PCA and LDA‐CV successfully discriminated two skin cancer‐relevant cell lines while detecting different amounts of nucleic acids, lipids, and proteins in distinct intracellular regions, further underscoring its potential as a clinical diagnostic tool. Copyright © 2013 John Wiley & Sons, Ltd. |
