GPD1 and neoplasm: Several proteins participate in lipid metabolism, namely A-FABP and cytoplasmic glycerol-3-phosphate dehydrogenase (GPDH-C), which were never detected in S samples; aldo-keto reductase 1B1 was found to be a less-abundant protein in D tumor samples; CEH and carboxylesterase 2/cocaine esterase (CE-2) showed the lowest level in both S and D tumor samples (Table 2).