SLC1A4 (ASCT1) is part of the alanine serine cysteine system, responsible for exchanging essential (threonine); non-essential (alanine, serine, and cysteine); and conditionally essential (glutamine) amino acids, making its overexpression a powerful prognostic biomarker related to cancer cell cycle progression, metabolism, proliferation, migration, anti-apoptosis, inflammation, and immunity [29,30]. Here, SLC1A4 is linked to cancer.