# Skin Cancer Metabolic Profile Assessed by Different Analytical Platforms
## 7 Skin Cancer Metabolomics Using Different Analytical Platforms
### LC-MS Based Skin Cancer Metabolomics  
Liquid chromatography-mass spectrometry (LC-MS) is another platform utilized by metabolomics. This technology combines the mass spectrometer's mass analysis abilities with the liquid chromatography's physical separation. An ion source, a mass analyzer, and a detector are the three main components of a mass spectrometer. Sample molecules are transformed into ions by the ion source, which are then resolved by the mass analyzer, either in an electromagnetic field or a time-of-flight tube, before they are assessed by the detector. Ion sources come in various forms, such as electrospray ionization (ESI), atmospheric pressure photoionization (APPI), and atmospheric pressure chemical ionization (APCI). To enhance metabolome coverage, it is sometimes necessary to examine the biological sample in both positive and negative ionization modes, using a scan range of m/z 50-1000 [50]. Significant advancements in chromatographic resolution and accelerated analysis have also been made recently with the help of ultra-performance liquid chromatography (UPLC), which is characterized by a pressure \(>\) 400 bar in columns packed with 2-m diameter particles [51]. For improved attribution of metabolites from chromatographic mass data, UPLC and MS are often hyphenated. To study the molecular changes between primary cutaneous melanoma and the nearby normal skin, [PERSON] et al. conducted a metabolomics analysis for primary melanoma and matched extra-tumoral microenvironment (EM) tissues, in order to widen temporal inferences related to the commencement of melanoma, and compared mismatched metastatic melanoma tissues to EM tissues to predict its progression. Utilizing a m/z of 70 to 1000, \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Skin vs. Air Samples** & **Non-Melanoma vs. Matching Skin** & **Melanoma vs. Matching Skin** \\ \hline \(\bullet\) & 5 keratinocyte carcinoma samples were analyzed against adjacent against 10 skin samples (five keratinocyte carcinoma and melanoma) & 5 fresh confirmed melanoma samples were analyzed against \\ \(\bullet\) & 10 air samples were analyzed against & matching control skin from the same patient. & 5 different matching control skin from the same patient \\ \(\bullet\) & 10 air samples were analyzed against 10 skin samples (five keratinocyte carcinoma and five melanoma) & \(\bullet\) No dysregulated metabolic features were identified between the two groups & \(\bullet\) Annotated volatile compounds identified to be significantly increased in melanoma samples relative to control skin were; \\ \(\bullet\) & 10 air samples were analyzed against 10 skin samples (five keratinocyte carcinoma and five melanoma) & \(\bullet\) No dysregulated metabolic features were identified between the two groups & \(\bullet\) Annotated volatile compounds identified to be significantly increased in melanoma samples relative to control skin were; \\ \(\bullet\) & 10 air samples were analyzed against 10 skin samples (five keratinocyte carcinoma and five melanoma) & \(\bullet\) No dysregulation metabolic features were identified between the two groups & 2-Ethlyhexyl-4-methoxycinamate, 1-eicosene, palmitic, lauric, and myristic acid. \\ \(\bullet\) & 10 air samples were collected at different times & \(\bullet\) No dysregulation metabolic features were identified as significant with P value differentially expressed features between adjacent control skin and keratinocyte carcinoma is expected. & Only one volatile compound, toluene was found to be decreased in melanoma samples relative to control skin. \\ \hline \end{tabular}
\end{table} 
Table 4: Comparison of metabolomic signature between three groups: skin vs. air samples, keratinocyte carcinoma vs. matching skin and melanoma vs. matching skin.