SLC6A14 and cancer: LC-MS/MS was used to determine 20 amino acids concentration in the culture supernatant of HCT116 cells and found that 16 amino acids (except L-histidine, L-ornithine, L-citrulline, and L-aspartic acid) concentrations were increased in the culture supernatant of HCT116 cells by silencing SLC6A14 with siRNA or pharmacological blockade of SLC6A14 with α-MT, indicating that SLC6A14 plays an important role in amino acid uptake in the SLC6A14-positive cancer cells (Table 2).