The evidence collected with SW480 colorectal cancer cells shows that: (i) treatment with NAC promotes increased expression and activity of mitochondrial enzymes (MST and SQR) involved in the production and consumption of H2S and sulfane sulfur species and (ii) NAC can act as a direct sulfane sulfur-accepting co-substrate for MST, being likely persulfidated (Figure 6). The gene discussed is SQOR; the disease is colorectal cancer.