Elevation of the L-citrulline/L-arginine ratio in MDA-MB-468 cells is thus suggestive of higher NO synthesis activity; this is in line with reports of upregulated activity of inducible NO synthase in triple-negative breast cancer and the induction of a basal-like transcription pattern in ER-negative patients [28–30]. The gene discussed is NOS2; the disease is triple-negative breast carcinoma.