Gastric cancer is one of the most common human malignancies, and its prevalence has been shown to be well-correlated with cancer-related deaths worldwide. Regrettably, the poor prognosis of this disease is mainly due to its late diagnosis at advanced stages after the cancer has already metastasized. Recent research has emphasized the identification of cancer biomarkers in the hope of diagnosing cancer early and designing targeted therapies to reverse cancer progression. One member of a family of growth-related nicotinamide adenine dinucleotide(NADH or hydroquinone) oxidases is tumor-associated NADH oxidase(t NOX; ENOX2). Unlike its counterpart CNOX(ENOX1), identified in normal rat liver plasma membranes and shown to be stimulated by growth factors and hormones, t NOX activity purified from rat hepatoma cells is constitutively active. Its activity is detectable in the sera of cancer patients but not in those of healthy volunteers, suggesting its clinical relevance. Interestingly, t NOX expression was shown to be present in an array of cancer cell lines. More importantly, inhibition of t NOX was well correlated with reduced cancer cell growth and induction of apoptosis. RNA interference targeting t NOX expression in cancer cells effectively restored non-cancerous phenotypes, further supporting the vital role of t NOX in cancer cells. Here, we review the regulatory role of t NOX in gastric cancer cell growth. Gastric cancer is one of the most common human malignancies, and its prevalence has been shown to be well-correlated with cancer-related deaths worldwide. Regrettably, the poor prognosis of this disease is mainly due to its late diagnosis at advanced stages after the cancer has already metastasized. Recent research has emphasized the identification of cancer biomarkers in the hope of diagnosing cancer early and targeted targeted therapies to reverse cancer progression. One member of a family of growth-related nicotinamide adenine dinucleotide (NADH or hydroquinone) oxidases is tumor- associated its counterpart CNOX (ENOX1), identified in normal rat liver plasma membranes and shown to be stimulated by growth factors and hormones, t NOX activity purified from rat hepatoma cells is constitutively active. Its activity is detectable in the sera of cancer patients but not in those of healthy volunteers, suggesting its clinical relevance. Interestingly, t NOX expression was shown to be present in an array of cancer cell lines. More important, inhibition of t NOX was well correlated with reduced cancer cell growth and induction of apoptosis. RNA interference targeting t NOX expression in cancer cells efficiently restored non-cancerous phenotypes, further supporting the vital role of t NOX in cancer cells. Here, we review the regulatory role of t NOX in gastric cancer cell growth.