SLC6A8 and melanoma: Another example is constituted by phosphocreatine, whose higher predicted levels are correlated with poorer prognosis in melanoma (Figure 4E, p = 4.4 × 10−8); we could report a very strong correlation between phosphocreatine metabolic levels and gene expression of SLC6A8 (Supplementary Figure S1), and both are known to be able to promote cancer progression [42] by promoting the cancer hallmark of energetic dysregulation [10].