SLC38A2 and breast carcinoma: In MCF-7 human breast cancer cells, chronic competitive inhibition of SNAT2 progressively reduced cell proliferation and induced a significant decline in intracellular concentrations of not only SNAT2 AA substrates (e.g., serine, glutamine, alanine, threonine) but of branched chain AAs (leucine, isoleucine and valine).