Raman spectroscopy of dried serum for the detection of rapid noninvasive multiple myeloma

Raman spectroscopy has recently emerged as an attractive focus of research interest in studies of hematological diseases. However, comprehensive Raman spectral analyses of serum samples from patients with multiple myeloma (MM) or other forms of lymphatic neoplastic disease are lacking. In this study, laser Raman spectroscopy and orthogonal partial least-squares discrimination analysis (OPLS-DA) were employed to develop a simple, noninvasive approach to MM diagnosis based on dried serum samples. To that end, systematic OPLS-DA analyses of dried serum from 35 patients with MM and 13 healthy controls were performed, revealing clear differences between these two groups in terms of the resultant serum spectral data. Specifically, significant reductions in the intensities of Raman peaks corresponding to nucleic acids (726, 781, 1579 cm^-1), proteins (621, 1603, 1616 cm^-1), lipids (1437, 1443, 1446 cm^-1) and carotenoids (957, 1160, 1520 cm^-1) were observed in MM, together with increases in the intensities of peaks corresponding to carbohydrates (920, 1123 cm^-1) and collagen (1345 cm^-1). Through combined analyses of serological indices associated with metabolic activity, MM patients were confirmed to exhibit elevated serum glucose levels and decreased levels of high-density lipoprotein cholesterol. These results offer a spectroscopic foundation for the relationships between MM classification and serological testing data, offering new evidence that can guide the early and efficient identification and characterization of this deadly cancer type. This exploratory study thus offers insight into the potential utility of Raman spectroscopy as a tool for the noninvasive detection of specific subtypes of MM.